Crocs (Nasdaq: CROX) has done it again -- and by "done it," I mean "disappointed investors." Just like last quarter, the footwear maker dumped a big bucket of murky swamp water on shareholders' once-heady optimism.

True, Crocs' fourth-quarter numbers were impressive at first glance. Net income surged 84.1% to $38.3 million, or $0.45 per share. Revenue skyrocketed 99.1% to $224.8 million. Companies like Heelys (Nasdaq: HLYS), Steve Madden (Nasdaq: SHOO), or Timberland (NYSE: TBL) would envy such earnings, right?

Still, several questions poke holes in Crocs fans' hopes. First, the gross profit margin dipped to 56% from 57.7% this time last year. Management optimistically noted that strong demand during the holidays necessitated pricey shipping by air freight, but that's small consolation to nervous shareholders, who probably feel like they got run over by the premium-momentum-stock-gone-downhill freight train. Meanwhile, SG&A expenses increased to 32% of revenue, from 30.9% last year.

In addition, Crocs merely reiterated its outlook for 2008, stating that it believes it will earn $2.70 per share on revenue of $1.16 billion. Wall Street analysts were looking for 36% growth, to $2.71 per share this year.

Here's arguably the most nagging nugget: those darn inventories. They burgeoned by 188% year over year, far outpacing Crocs' revenue growth.  And accounts receivable increased 133% to $152.9 million. That's not quite as bad as last time around, but I'm sure shareholders would rather see far better progress. After all, both metrics can be red flags when they're increasing at a higher rate than sales, and Crocs is fast losing the benefit of the doubt.

I have to admit that Crocs appears a lot cheaper than it did a few months ago, having fallen 45% over the last six months. Just for starters, it's trading at just 10 times 2008 earnings, which are expected to grow more than 35%, right? But I'm not really changing my tune. Personally, I'm still not convinced that Crocs really has a sustainable competitive advantage, as cheap as its stock might appear at the moment. I'm haunted by visions of an ever-higher mountain of colorful shoes, as demand for a faddish product weakens.

As far as I'm concerned, there are still plenty of holes in the Crocs investment thesis (particularly for long-term investors). There's nothing wrong with searching for reasonably priced stocks with far less fad-fashion risk.

For related Foolishness:

If you're looking for awesome companies at great prices, take a 30-day free trial of Tom and David Gardner's Motley Fool Stock Advisor.  

Alyce Lomax does not own shares of any of the companies mentioned. The Motley Fool's disclosure policy is hole-resistant.