Photovoltaic phenom First Solar (Nasdaq: FSLR) released its second-quarter results late last week. The numbers looked quite good, but shares were hit hard on Friday and are showing little to no bounce today. Is this a buying opportunity in the best-of-breed solar module manufacturer?

I would suggest caution, for a number of reasons.

First of all, a revenue "beat" relative to Wall Street analyst expectations, such as we saw this quarter, isn't as meaningful as it used to be. With the move to a hybrid manufacturer/EPC (engineering, procurement, and construction) business model, First Solar's top-line results are choppier. A lot depends on the timing of revenue recognition on large projects with customers like Enbridge (NYSE: ENB) and Sempra Energy (NYSE: SRE).

As for the 2010 outlook, First Solar raised its full-year earnings per share guidance to $7 to $7.40, but analysts were already penciling in results at the high end of prior guidance. This boost is largely the result of a shift in product mix (away from the lower-margin EPC business in favor of more module sales), rather than an increase in sales. So that aspect of the report was hard to get excited about.

Here's the most important consideration, in my view. While there's talk of stable or rising pricing among crystalline PV players like Suntech Power (NYSE: STP) or Trina Solar (NYSE: TSL), First Solar is clearly facing more pricing pressure going forward. The company says its second-half pricing "supports the sell-through of our modules after [feed-in tariff] changes and positions us for 2011 FiT." The company is dealing with both this year's and next year's subsidy reductions, and each will chip away at margins.

Between the margin erosion resulting from pricing pressure and the EPC business, it's hard to see First Solar cranking out really strong results in 2011. It's true that the company is performing like a champ on the cost side, but I'm not sure that's enough to drive the kind of financial results that are priced into the stock, even after the recent sell-off. If you think next year's per-share earnings will roughly match this year's -- which is the forecast among the more cautious Wall Street shops -- then the shares don't look like a steal.

For now, I'm sticking with my outperform calls on Solarfun Power (Nasdaq: SOLF) and Applied Materials (Nasdaq: AMAT) as better bets for the back half of 2010.

Fool contributor Toby Shute doesn't have a position in any company mentioned. Check out his CAPS profile or follow his articles using Twitter or RSS. First Solar and Suntech Power Holdings are Motley Fool Rule Breakers picks. The Motley Fool has a disclosure policy.