Another quarter. Another beat. Another raise. (Honestly, folks, Under Armour's (NYSE: UA) overachievements are starting to get a little boring.) Here are this week's relevant stats:

  • Sales were up 42% in comparison to last year's Q2 -- $291 million.
  • Earnings nearly doubled to $0.12 per share -- 50% ahead of the original estimate.
  • Best of all, the company's laggard footwear business appears to be picking up the pace. Sales gained 31% in comparison to last year.

And going forward, Under Armour promises more of the same. With growth going great, CEO Kevin Plank pledged to finish out this fiscal year with 34% sales growth and 40% better operating profit than last year.

Great news, right? Well, not so fast. Shares are trading down today -- and there's actually good reason for that. Once again, Under Armour reported that accounts receivable and inventories grew faster than revenues during the quarter (up 45% and 74%, respectively.) Once again, free cash flow suffered from Under Armour's poor cash management. After burning through $27.5 million in free cash over the course of H1 2010, Under Armour shoveled even more cash in the furnace in H1 2011. Free cash flow for this first half ran negative to the staggering sum of $113.8 million.

Foolish takeaway
Maybe I'm just old-fashioned, but I've always been partial to investing in companies that actually earn cash from their businesses, rather than consuming it. Companies like Nike (NYSE: NKE), for example. Last month, Under Armour's archrival "beat earnings" just like Under Armour did -- but it did so while generating positive free cash flow of $713 million. Elsewhere in footwear, Deckers (Nasdaq: DECK) is churning out nearly $100 million in annual free cash flow. Timberland (NYSE: TBL) -- soon to become part of VF (NYSE: VFC) -- is FCF-positive by more than $50 million. Wolverine World Wide (NYSE: WWW)? $17 million. Heck, even Crocs (Nasdaq: CROX) is creating cash these days -- nearly $60 million over the past 12 months.

I don't own any of these stocks, mind you. But I'd buy any one of them before I'd even consider trying on Under Armour.

Time to chime in
Like I said, though -- that's just me. I know other Fools think differently, and at least two Motley Fool newsletter teams have recommended the stock. So feel free to disagree. Tell us what you think about Under Armour's quarter on Motley Fool CAPS.