The solar reporting season started out sunny, but it's ending with a whimper.

A lot of the dreariness has to do with events subsequent to Sept. 30, so the fact that firms like SunPower (NASDAQ:SPWRA) reported early reflects a lot of that optimism. More recent quarterly calls -- like those from JA Solar (NASDAQ:JASO) and ReneSola (NYSE:SOL) -- have revealed solar rot.

Rounding up the third-quarter reports were Yingli Green Energy (NYSE:YGE) last week and Solarfun Power (NASDAQ:SOLF) today. As both firms are Chinese photovoltaic players, a little compare and contrast should serve us well.

In terms of margins, Yingli reported far stronger numbers. Solarfun, on the other hand, took a number of charges, stemming from unusable materials, inventory writedowns, and prepayments considered "at risk." That last issue is exactly why I've previously cast an uneasy eye on rising prepayments as a percentage of firm assets -- though ironically, it was Yingli that had me nervous on that front. Even without the charges, Yingli's margins were still significantly higher than those of Solarfun.

Like Suntech Power (NYSE:STP), Solarfun announced that it's placing further expansion on pause. Yingli, on the other hand, is pushing forward with a capacity expansion to 600 megawatts, due by the third quarter of 2009. Part of Yingli's borrowing base is now a long-term credit facility, in contrast to the usual short-term bank borrowings most often employed by Chinese growth companies.

A comment by Solarfun that the firm expects to be cash flow-positive in the second half of next year wasn't too thrilling, considering that Trina Solar (NYSE:TSL) has already hit this milestone. Still, the firm's cash collection does appear fairly strong, with days sales outstanding coming in well below that reported by Yingli.

For now, I'm not crazy about either name, but Yingli appears to be the more sound of the two solar shops. Fools seem to agree, having awarded Yingli five stars in Motley Fool CAPS, versus Solarfun's three. Make an outperform call on your favorite -- Yingli or Solarfun -- today.

Suntech Power is a Motley Fool Rule Breakers recommendation. See if you take a shine to any of our premium newsletters with a free 30-day trial.

Fool contributor Toby Shute is active in CAPS under the name TMFSmashy, but he doesn't have a position in any company mentioned. The Motley Fool has a disclosure policy.