Dramatic stories about the economy and markets are what sell financial newspapers. Ironically, it’s the microeconomic stories that wind up driving investor returns.

That’s particularly true in an environment of slow and jagged economic growth, such as what we have today. Some companies are able to adapt and remain healthy in tough times, boosting dividends and eventually commanding premium share prices. Others simply can’t. Weighed down by debt or too much operating risk, they falter.

A brief look at the MLP Profits How They Rate table tells the tale. The column “Total Return” shows how each of the MLPs we track has performed over the 12 months–change in unit price plus distributions. It’s continuously updated, as are the table’s data for price, yield and dividend amount.

The past year has been among the more volatile in memory, for the overall market as well as MLPs in general. The Alerian MLP Index–the benchmark capitalization-weighted index of the 50 largest energy-focused MLPs–is currently about 4 percent above where it began the year. Coupled with a yield of a bit more than 6 percent, the index has generated a total return of roughly 10 percent, about three times the return for the S&P 500.

That’s not bad at all, particularly in a year that’s seen so much uncertainty for the economy and global credit markets. And MLPs have been further hampered as an asset class by misplaced worries that they’ll face new taxes as part of Uncle Sam’s efforts to restore some semblance of fiscal balance.

The Alerian MLP Index’s generally solid showing, however, masks some pretty deep divisions in the MLP universe itself. We’ve been able to warn readers about the likes of AllianceBernstein Holding LP (NYSE: AB), which has dropped more than 40 percent over the last 12 months, mainly because these companies don’t operate energy-related assets.

Non-energy MLPs could wind up being socked with massive new taxes, should legislation to tax “carried interest” be revived as seems likely. Meanwhile, their businesses aren’t necessarily well suited to paying out a hefty amount of profits over the long term. And there’s nothing like tough economic times to bring out the bad. AllianceBernstein, for example, cut its distribution again in July, by about 20 percent.

On average, our Conservative Holdings are up about 12.5 percent. Our Growth Holdings are up 7.8 percent and Aggressive Holdings are 5.8 percent. That too is roughly in line with the performance of the Alerian, and is actually a little higher when including gains from the sale of EV Energy Partners LP (NSDQ: EVEP) earlier this year.

That performance too, however, also masks some large differences between individual MLPs. Our worst performer by far over the past 12 months, for example, is Inergy LP (NSDQ: NRGY), which had dropped roughly 27 percent, pretty much all of it since May. And our position in Navios Maritime Partners LP (NYSE: NMM) has also eroded a bit, with the units down about 18 percent over that time.

Every portfolio, of course, has its divergences. The important thing is not to lose sight of the only thing that’s really important–the total return of your entire portfolio.

More often than not, if you’ve chosen a portfolio of good businesses, today’s loser will become tomorrow’s big winner. Much of the recent decline we’ve seen in certain MLPs–as well as other dividend-paying stocks–has been due to an overall “de-risking” of portfolios.

Logically, riskier dividend-paying stocks and MLPs will always trade at a higher yield than less risky peers. Earlier this year, that yield premium shrank dramatically, as investors seemed to lose their fear. Starting in May, however, it has widened back out, often violently.

As a result, there are now 28 MLPs in our How They Rate universe that yield at least 8 percent. That’s versus a half dozen or so just a few months ago.

Some of these MLPs are being priced with too much risk, simply because of the general de-risking in the market. Odds are they still carry more risk than say a Conservative Holding like Enterprise Products Partners LP (NYSE: EPD). But once the markets calm, they’ll narrow the yield gap quickly, providing hefty capital gains for their owners. That’s in addition to what in many cases are still rising distributions.

On the other hand, some of these MLPs are arguably not pricing in enough risk, given their business weakness and the likelihood we’re going to be stuck in a slow growth environment for some time. Invariably we’re going to be better off out of them, despite their hefty yields.

Below we take a brief look at all the current members of the “8 percent and up” club. We highlight what’s worth buying, what’s worth holding and what you should sell now before further damage is done.

Note these are shown in alphabetical order, not by order of preference. Current advice for each is shown right after name and symbol.

AllianceBernstein Holding LP (NYSE: AB)–SELL. AllianceBernstein is a longtime sell recommendation in MLP Profits for its exposure to potential carried interest tax legislation. But its dividend history should give any income investor cause for pause. In the past two years, the quarterly payout has been as high as 67 cents per unit in November 2009 and as low as 12 cents in November 2010.

The most recent payment of 34 cents declared Jul. 29 is 20 percent below the payment declared in May. That followed lower than forecast second quarter earnings. Profits generally track the health of global markets, which likely means an even weaker third quarter result.

America First Tax Exempt Investors (NSDQ: ATAX)–SELL. This one hasn’t done as poorly as AB, probably because it’s been able to pay the same distribution since mid-2009, when it cut the payout 7.4 percent. But it’s fair to ask just how this dividend is being financed at a yield of 9.5 percent when the federally tax-exempt mortgage bonds it owns are paying out so much less.

New bonds acquired during the second quarter, for example paid out only between 6.5 to 7.75 percent. What you really have here is a closed-end fund masquerading as a limited partnership because tax loopholes currently allow it–and very likely scrambling for cash with leverage and asset sales to hold its payout. Then there’s the fact that this is hardly an area of economic strength.

Boardwalk Pipeline Partners LP (NYSE: BWP)–Buy @ 30. This owner of pipelines and other fee-based energy infrastructure has been body slammed this year despite 21 consecutive quarterly distribution increases. The decline began in late April, when a 16 percent drop in distributable cash flow appeared to disappoint some investors. Selling picked up again over the summer, following second-quarter results that disappointed even more.

The underlying business itself, however, continued to hold few risks for investors, with 14,000 miles of pipelines and related assets with fees locked up by long-term contracts. The 167 billion cubic feet of natural gas storage capacity is 80 percent reserved under contracts that pay even if not used, with only 5 percent of volume subject to market conditions.

Even with the shortfall this year, distributable cash flow still covered the payout and there are many opportunities for growth. In short, this one looks like an MLP where investors are pricing in too much risk.

BreitBurn Energy Partners LP (NSDQ: BBEP)–Buy @ 20. This producer of oil and gas has increased its payout five times since restoring a regular dividend in February 2010. Output is half oil, half gas, with reserves centered around long-life (low decline rate) proven sources in six US states. Financial policy is conservative, with management striving to maintain 20 percent or less utilization of its credit facilities. Distribution coverage is roughly 1.2-to-1, and management targets low- to mid-single digit distribution growth, allowing it to finance capital spending without overly relying on capital markets.

Hedging is aggressive, with prices for 80 percent of expected oil and gas output locked in for the next 12 months, 70 percent the 12 months after that and 60, 50 and 40 percent for each year subsequently. Plans call for adding CD300 million to CAD350 million in assets for all of 2011, a pace that should keep cash flow rising. We prefer our Portfolio producers, such as Linn Energy LLC (NSDQ: LINE). But for those looking for something a bit more aggressive, this one is attractive.

Calumet Specialty Products Partners LP (NSDQ: CLMT)–SELL. Hopefully, MLP Profits readers have heeded our long-time “sell” recommendation for this processor of petroleum products. Units have plunged from above $24 to a little more than $16 since late July.

The good news is the MLP now appears to have financed the purchase of the Wisconsin refinery it made earlier this year under decent terms. But refining is a competitive and volatile business that’s never been conducive to big distributions over the long pull, and distribution coverage here isn’t particularly robust, either.

Capital Products Partners LP (NSDQ: CPLP)–Buy @ 10. The MLP’s merger with Crude Carriers Corp (NYSE: CRU) is now approved and set to close Sept. 30. That should remove a major cloud of uncertainty. Management has once again affirmed the post-merger distribution, with 85 percent of cash flow needed to sustain it locked in by Capital Products’ pre-merger fleet. Management also has the flexibility to fix the former Crude’s carriers to long-term contracts over time, rather than when conditions are weak.

Like all tankers, Capital’s unit price continues to be weighed down by weak market conditions. But as long as the distribution holds, this one looks set to recover sharply. It’s still a buy for more aggressive investors.

Cheniere Energy Partners LP (AMEX: CQP)–SELL. Management continues to show its acumen raising capital, including 3 million more units earlier this month. But it’s still woefully short of needed funding to deliver on the hype it’s pitched to the markets, mainly that it can start exporting liquefied natural gas anytime soon at its existing import-focused facilities.

The current distribution is supported by contracts that have a ways to run. But there’s nothing here for growth or long-term income. Maybe that’s why the units have plunged from nearly $20 to barely $13 the last two months.

Encore Energy Partners LP (NYSE: ENP)–Buy @ 24. We’re sticking with this Aggressive Holding until it completes its merger with Vanguard Natural Resources LLC (NYSE: VNR), which currently owns 46 percent of the oil and gas producer. That deal still looks on track to create a much more powerful company later this year.

In the meantime, Encore has enhanced its current portfolio with the purchase of $47.6 million of oil and liquids weighted (83 percent) production in the Gulf Coast area. Management has shown itself more willing to adjust distributions to energy prices, which has made the units sometimes more volatile. But this situation is still moving in the right direction, and we’re holding in.

Energy Transfer Partners LP (NYSE: ETP)–Buy @ 50. This Growth Holding’s unit price has been soft for most of this year, coming down from the mid-50s to the low-40s since early May. The primary reason is management’s continued aggressive expansion moves, which have apparently delayed the return to robust distribution growth that had been alluded to earlier.

One of these is a joint venture with affiliated MLP Regency Energy Partners LP (NYSE: RGP) to develop natural gas liquids infrastructure. The other is the prospective purchase of 50 percent of a Florida gas pipeline for $2 billion, which would happen only if general partner Energy Transfer Equity LP (NYSE: ETE) successfully acquires Southern Union (NYSE: SUG). We’ll likely see a unitholder vote on that deal later this year. But until it’s either abandoned or Energy Transfer permanently finances the pipeline buy, these units will face head winds.

The good news is the distribution is safe, so this is really just a waiting game for those who own Energy Transfer Partners.

Exterran Partners LP (NSDQ: EXLP)–Hold. The natural gas compression business should be robust for years to come. And the MLP has boosted its distribution twice in the past 12 months to reflect successful expansion and $900 million in debt reduction since 2007.

Unfortunately, the near-term picture is difficult, with management admitting in August that it wouldn’t meet a cash flow growth target of 5 percent in 2011 and in fact will be below 2010 levels. That’s in large part because the company’s service of traditional markets is shrinking faster than the shale-focused business is growing. That shouldn’t be the case for long. But with the CEO stepping down because of missed targets, there’s a risk conditions will stay tough.

Distribution coverage should run about 1.2-to-1 the rest of the year, providing decent support to the dividend.

Ferrellgas Partners LP (NYSE: FGP)–Hold. The distributor of propane enjoyed a 27 percent increase in revenue for its fiscal fourth quarter, though gross profit was flat due to customer conservation and a 46 percent jump in the wholesale cost of propane. A 6 percent boost in propane sales volumes was encouraging, demonstrating management’s skill at adding new business in subpar operating conditions and cost controls. Interest expense was cut 10 percent.

On the downside, distributable cash flow was off 22 percent, pushing the payout ratio up to 122.6 percent for the full year. That’s obviously not sustainable, unless there’s a strong boost in distributable cash flow next year. But there’s little reason for investors to take that chance, even for a 10 percent yield.

Global Partners LP (NYSE: GLP)–Hold. This MLP is still growing, with product volume rising 53 percent in the most recent quarter, fueling a 39 percent jump in gross profit.

Unfortunately, distributable cash flow was lower by about 17 percent in the second quarter, affected by margin pressures that pushed up the cost of raw materials at the distributor of refined petroleum products. Last year’s acquisition of ExxonMobil’s (NYSE: XOM) gas stations and supply rights was a major plus.

But light distribution coverage means no growth in the distribution, which will hold back the unit price.

Inergy LP (NYSE: NRGY)–Hold. This propane distributor and owner of midstream energy infrastructure plans to split up later this year, pending unitholder and regulatory approval. Inergy Midstream LLC is expected to trade as NRGM on the New York Stock Exchange (NYSE), though the official listing is still pending. It appears that until this split occurs, a cloud of uncertainty will hang over Inergy LP’s unit price.

Over the most recent 12 months coverage of the payout by distributable cash flow was just 0.8-to-1, as margins from both midstream assets and propane distribution lagged expectations. Management has maintained that overall distributions post-spinoff will hold. But until that’s official, this otherwise seaworthy MLP will linger under a cloud of uncertainty. We’re sticking with it, but as a hold for now.

KKR Financial Holdings LLC (NYSE: KFN)–SELL. This one is squarely in the crosshairs of any attempt to tax carried interest. And don’t be taken in by the high yield, either. Quarterly dividends are all over the map, with a 21 cents payout in May falling to just 11 cents in August. It’s a volatile business that has no place in the MLP universe.

Legacy Reserves LP (NSDQ: LGCY)–Buy @ 32. This oil and gas producer has increased its payout for three consecutive quarters and posted very strong second quarter results. As management revealed in a Sept. 27 investor presentation, the LP has many plans to expand by buying proven oil production. Insider ownership is up to 24 percent of outstanding units, always a good sign.

The unit price has come off from its highs due to lower oil prices. That makes now a great time to buy into a well managed company with a compound annual growth rate of production of 25 percent since 2007.

Martin Midstream Partners LP (NSDQ: MMLP)–SELL. The company is in what should be fairly stable businesses. On the other hand, maintenance capital expenditures have been hurting cash flow coverage of dividends, which fell to just 0.95-to-1 in the second quarter. That should wind down at some point, providing an improvement in distributable cash flow in the second half of 2011.

But despite the high yield, there are better choices in the midstream area, such as all of our Conservative Holdings.

Navios Maritime Partners LP (NYSE: NMM)–Buy @ 20. We probably get more questions about Navios than any other Portfolio stock, for the obvious reason that shares have been volatile, and mostly to the downside lately.

As we’ve pointed out, however, management has covered its bases with long-term contracts and continues to expand, which allowed the dry-bulk tanker company to boost its distribution 2.3 percent in late July. Rather, Navios is cheap because of the conventional wisdom that all tanker stocks are doomed.

No one should really load up on any one stock. But stocks with 13 percent yields that have just hiked dividends are a rare breed indeed.

Natural Resource Partners LP (NYSE: NRP)–Buy @ 25. We already have one MLP in the Portfolio that makes its money off royalties from coal produced from its lands, Penn Virginia Resource Partners (NYSE: PVR). But this one has come well off its highs the past couple months, and the market for its coal remains robust, particularly for more valuable metallurgical coal used in steel. Met coal was almost half coal royalty revenue the first six months of 2011.

Management still expects 10 percent revenue growth this year overall, and distributable cash flow grew 32 percent, for distribution coverage of 1.46-to-1. That’s a very solid package.

Niska Gas Storage Partners LP (NYSE: NKA)–Hold. The gas storage business has been weak, so it’s no great surprise this stock has been weak. The good news is general partner (GP) Carlyle/Riverstone is still supportive and intends to maintain the current payout, despite coverage of just 0.7-to-1. The GP will reinvest its distributions to cut debt and hold the payout.

On the other hand, this business is weak, and prospects for recovery are unknown. That’s not a good combination of anyone hunting for income.

NuStar Energy LP (NYSE: NS)–Buy @ 65. The owner of energy midstream infrastructure and refiner/marketer of asphalt boosted its quarterly payout by 1.9 percent in late July. That’s a vote of confidence in its current payout, even as management continues to expand its presence in natural gas liquids and strengthen its pipeline relationship with former parent Valero Energy Corp (NYSE: VLO).

Some $136 million in new growth projects are expected to add to second half 2011 cash flow. Weak asphalt market conditions and a sizeable take from NuStar GP Holdings LP (NYSE: NSH) are likely factors holding down the unit price and pumping up the yield now.

But patient capital spending should keep cash flow rising going forward, and dividends along with it. A possible future take-in of the general partner could provide another bonus, though management remains coy on timing.

Oxford Resource Partners LP (NYSE: OXF)–Hold. This one has emerged as one of the bigger losers in the How They Rate universe this year, despite a business (coal mining) that has been thriving. Costs appear to be the biggest problem, as distributable cash flow actually swung negative in the second quarter of 2011, despite an 8.7 percent boost in revenue.

The company believes it will recover these costs going forward, and as flooding becomes less of an inhibiting factor on sales. Management maintains meanwhile that it expects to fully cover the minimum quarterly distribution as laid out in its launch, or 43.75 cents per unit. But this is not as high percentage a situation as Penn Virginia Resource Partners or Natural Resource Partners.

PAA Natural Gas Storage LP (NYSE: PNG)–Hold. The weakness of the gas storage business almost surely explains the losses here since late July. Management has reduced its distribution growth guidance for 2011 once, and there may be another cut coming.

That said, the assets look solid and the company has solid backing from Plains All-American Pipeline LP (NYSE: PAA), so there’s little risk to the distribution at this point, though little upside until gas storage market conditions improve.

Penn Virginia Resource Partners LP (NYSE: PVR)–Buy @ 29. The price has come down with worries about the global economy and a possible slacking of demand for coal. As of now, however, this combination coal royalty and gas midstream company looks like it will have no problems continuing to grow it distribution, with another boost likely in late October.

A pipeline venture with Aqua America (NYSE: WTR) in the Marcellus Shale to supply fresh water to producers could open up a whole new line of business for Penn Virginia and expands its presence in Marcellus shale. This is the lowest-risk of the coal-focused MLPs and still a solid buy.

QR Energy LP (NYSE: QRE)–Buy @ 22. This oil and gas producer is following the course set by our other favored producer MLPs. That is acquiring proved, long-life reserves of oil and gas that immediately add to distributable cash flow per unit.

One good example was the purchase of 37.1 million barrels of oil equivalent reserves in mid-September. As is the case with all producer MLPs, investors can expect unit prices to follow energy prices, even if output is hedged. But that also offers opportunistic times to buy in at good prices.

Rhino Resource Partners LP (NYSE: RNO)–Hold. This MLP is also focused on coal production and marketing and has taken a hit in unit price from economic worries. A limited trading history makes it a somewhat lower-percentage bet that Penn Virginia and others, though the higher yield provides some compensation.

We like the assets but would like to see some more action before recommending “buy.”

StoneMor Partners LP (NSDQ: STON)–SELL. We don’t like MLPs that aren’t involved in energy. This one owns and manages cemeteries.

Terra Nitrogen Company LP (NYSE: TNH)–SELL. Economic worries appear to have reversed what had been a parabolic rise for this fertilizer company. The bigger worry for investors who’ve been sucked in, however, is the fact that the distribution is extremely variable.

The payout declared in early August is generous at $3.75 per unit, but 22.5 percent below the payout declared in May. Those chasing the high yield could be very disappointed, even if fertilizer prices stay relatively solid.

Vanguard Natural Resources LLC (NYSE: VNR)–Buy @ 30. The acquisition of Encore Energy (see above) appears to be what’s dragging on this producer of long-life gas and oil reserves. Nonetheless, management looks likely to boost the payout for a fourth time this year when it declares the next distribution in mid-October.

That’s because it continues to be successful locking in new low-cost production, as we’ve reported here. This is still a very good one selling at a great price. Note we’ll add it to the Aggressive Holdings when the Encore takeover deal is complete.