Keith Law's summary of the Pence deal (Insider-Only) has a lot of great information, including this quick summary:
I'd call it a reasonable return, but not a great one, given the risk attached to both of those prospects. This deal could easily result in disaster for Houston...if the red flags on these prospects (especially Cosart) prove prophetic.
I do think a player who's more than a rental should return one prospect of a little more certainty than either of these two guys can offer, or that it should have included one more major prospect from Philadelphia.
SI's Cliff Corcoran:
At the moment, this looks like a good deal for both sides. The Phillies might have overpaid for Pence, but their potential reward (one if not multiple world championships) is worth the risk...Cosart and Singleton are both a long way from the majors in terms of development, and a lot could go wrong with either one, but getting two top prospects, a potential front-of-the-rotation starter and potential middle-of-the-order bat, for essentially a league-average outfielder is a trade any rebuilding organization needs to make.
the best advice at this juncture is to read about Cosart's electric stuff and Singleton's projectable power and hope for the best, but, naturally, be patient with the process. The Astros are smart to be acknowledging not only their place in the standings this season, but their realistic contention hopes in 2012. They were right to dangle Pence at a time when his trade value is at its peak and his production is getting them nowhere.
the Phillies did not trade -- and the Astros did not trade for -- a truly outstanding, can't-miss prospect. The Phillies traded for a couple of Florida State League players who will probably reach the majors but might not do much more than that. Singleton and Cosart are both too far from the majors to say more than that.
Ed Wade may have made some questionable moves in the past, but it’s hard to argue that he isn’t currently steering the Astros in the right direction.
My opinion is that the Phillies should have been able to get more if they were parting with Jonathan Singleton and Jarred Cosart in the same deal. Those are two of the top 50 prospects in the game. I think it’s a better return than what the Padres got for Adrian Gonzalez from the Red Sox. It’s far, far better than what the Phillies got when they traded Cliff Lee to the Mariners a year and a half ago, and it’s probably more than what they gave up for Roy Halladay. Even the best players don’t generally net the kind of return Pence just did.