When we started this advisory in spring 2009, we resolved to cover every single US master limited partnership.

Since that time our task has become considerably more difficult, as MLPs’ popularity has induced more companies (including existing MLPs) to monetize assets by packaging them into new entities.

Like mergers, IPOs create excitement because they promise out-of-the-ordinary investment returns. And indeed there are notable success stories among the recent raft of IPOs.

In January, for example, we advised investors to swap their units of Inergy LP (NYSE: NRGY) for the MLP’s recent IPO offering, Inergy Midstream LP (NYSE: NRGM).

Our reason was Inergy Midstream included only a stake in Inergy’s midstream energy assets focused on natural gas and natural gas liquids storage in the Northeast US. Switching allowed us to continue participating in the growth of those assets while avoiding Inergy LP’s considerably less profitable exposure to propane distribution.

Inergy Midstream has returned nearly 20 percent since we recommended the swap, fueled by three distribution increases along the way. Meanwhile, Inergy LP has been all over the map en route to cutting distributions twice, from USD0.705 per unit in February to USD0.29 now.

New Conservative Holding Oiltanking Partners LP (NYSE: OILT) is another success story. We’re only adding it, however, after the unit price has a year-plus trading history, and the company has an equal record of distribution growth, which now appears to be accelerating.

Below I look at recent IPOs of MLPs and how they stack up as investments now and in the future. I examine their value, growth potential and prospects if they’re forced to rely more on their own resources by slightly less favorable capital market conditions.

EQT Midstream Partners LP (NYSE: EQM) is off a good start as a business from its June 2012 initial public offering. EQT Corp (NYSE: EQT) holds 17 percent of the limited partner units and the general partner interest in this operator of midstream assets serving the Marcellus Shale region of southern Pennsylvania and northern West Virginia.

That means plenty of opportunities for asset drop-downs to fuel dividend growth, as the general partner fuels its expansion into liquids-rich areas of the region. Distributable cash flow roughly covered the initial distribution. And management raised guidance for cash flow growth, which should fuel payout increases going forward.

EQT Midstream’s current yield is 4.6 percent, which is on the low side for what I’d like to see. That’s the result of an almost uninterrupted rise in unit price since the IPO, and it’s a good reason to rate this MLP a hold for now. Note we first reviewed EQT Midstream in Elliott Gue’s Sept 2012 article Our Initial Take on Initial Public Offerings.

Hi-Crush Partners LP (NYSE: HCLP) was also highlighted in that article, though it hasn’t performed as well due to sensitivity to commodity prices.

The MLP also hasn’t paid a full quarterly distribution since its Aug. 15, 2012, IPO, so no doubt it’s being valued lower than it should be on that basis as well. The minimum distribution rate is USD0.475 per unit per quarter, which equates to a full-year yield of 9.2 percent.

Hi-Crush’s niche is manufacturing the specialized mineral “monocrystalline sand” used in hydraulic fracturing to drill oil and natural gas from shale. Reserves are located in Wisconsin.

We’ll get our first look at how Hi-Crush’s operating numbers stand up when management releases earnings on or about Nov. 14. Until then it’s a hold.

Linn Co LLC (NSDQ: LNCO) is actually not a master limited partnership itself. Rather, each share of last month’s initial public offering represents one unit of MLP Profits Portfolio Holding Linn Energy LLC (NSDQ: LINE).

Linn Co as a whole will hold 13.2 percent of the partnership, which will use the USD1.1 billion raised from the offering to retire debt. Much of this was taken on to buy USD2.23 billion in gas field in Kansas and Wyoming from BP Plc (NYSE: BP) earlier this year. Linn Co itself holds no other assets besides that 13.2 percent stake in Linn Energy, and its returns will depend fully on how well the Linn Energy performs.

For example, if Linn Energy maintains its current annual payout rate of USD2.90 per unit, Linn Co shareholders will recent between USD2.75 and USD2.84 after taxes.

Why own Linn Co over Linn? One reason might be that Linn Co isn’t taxed as a master limited partnership, so there are no K-1s. It also right now boasts a slightly higher yield.

We’ll continue to hold Linn Energy in the MLP Profits Portfolio, however, precisely because it is an MLP.

Note that we won’t be tracking Linn Co in How They Rate, but investors who opt to switch (Linn Energy unitholders did not receive shares of the IPO) can still keep up with its Linn Co’s prospects by tracking the fortunes of the LP.

Rentech Nitrogen Partners LP (NYSE: RNF) has attracted some readers for its high yield, which based on the payout declared for Nov. 14 is USD0.85 per unit. That equates to an 8.6 percent yield based on the current price.

The distribution, however, is 27.4 percent lower than what was declared for payment Aug. 14. That’s a clear warning not to expect level payments from this producer of nitrogen fertilizer products, primarily anhydrous ammonia and urea ammonium nitrate solution (UAN).

Rentech has been a winner for investors so far, nearly doubling from its initial public offering price of USD20 a year ago. There has been insider buying, including in the past month. And the LP has been able to make acquisitions as well to expand its business, including the purchase of a production facility in Pasadena, Texas, announced last week that will be accretive to cash available for distribution starting next year.

Earnings due out Nov. 8 should paint the picture of a company that’s growing its business, which over the long haul is how any commodity-sensitive company builds value. But investors should also be prepared for volatility in terms of price and demand for product, as we’ve seen in other segments of the fertilizer market.

Anyone who bought Rentech units for conservative income should definitely take advantage of the all-time high in the unit price to sell now. Aggressive investors can still hold on the promise of future growth, though only with the understanding this is not a “safe” dividend.

Seadrill Partners LLC (NYSE: SDLP) is perhaps the most unusual IPO of the current batch. Offered on Oct. 18, 2012, at a price of USD22 by parent Seadrill Ltd (NYSE: SDRL), the IPO starts out with ownership of four major drilling rigs, all of which are under contracts with super oils at least through March 2015.

The partnership also has deals in place for further drop-downs of rigs over the next five years from parent Seadrill.

The parent and general partner continues to own 78.8 percent of common units, as well as the general partner interest, ensuring it will continue to get the lion’s share of cash flow from the business. That includes a new class of “subordinated units” not being offered.

What do the LP unitholders get? Seadrill has stated it will pay a minimum quarterly distribution of USD0.3875 per unit. That equates to an annualized yield of around 7 percent for partnership units, and it should be protected by the long-term contracts on the rigs, given the payers are the likes of BP, Chevron Corp (NYSE: CVX), Exxon Mobil Corp (NYSE: XOM) and Total SA (NYSE: TOT).

On the other hand, renting and operating drilling rigs is one of the most fiercely competitive and cyclical businesses in the world. Once these contracts run out, the partnership’s cash flow visibility ends abruptly. If energy prices and drilling activity are robust globally–and these rigs are still considered desirable to rent–cash flow could be sustained.

If not, cash flow will drop, and unless Seadrill Partners can replace it so will the distributions. The history of Seadrill’s own dividend–which was suspended entirely for a year in late 2008–should give anyone seeking a safe payout some very real cause for pause.

We don’t track Seadrill Ltd in MLP Profits. But it looks like by far the better deal, both for a higher yield and a more honest presentation of risk. Seadrill Partners looks, at best, like something to avoid at least until there’s a more established trading history and track record for paying dividends.