Checking in from Cincinnati on my mom's computer, and just saw the trade.
First, Hamilton's going to hit the crap out of the ball in Texas.
As for the Reds' return on him, Volquez looks like a pretty exciting arm. Granted, he's got control issues, but I'm sure Krivsky et al. think they can fix that. But here we have a guy who's already pitched a few innings in the big leagues, just turning 25, and can throw the ball a million miles an hour. He's the sort of guy who could step in and over the next year or two become a dominant starter. Sure, he might not. But this kind of pitcher is exactly the sort of pitcher that smart ballclubs go after. Between he, Bailey, and Cueto, you have to think that at least one of them will pan out to be a quality guy. And it's not unreasonable to hope that two of them will. That, plus another modest splash from someone like Maloney, Wood, Watsin, or whoever, and the Reds have a great shot at a very, very good young rotation in the coming years.
Herrera is kind of a surprise to me, because Doug's reports indicate that he's pretty small and throws a trick pitch (screwball/change). ... Sounds like Guevara (the guy we lost in the Rule 5 draft), and that's the sort of pitcher that Krivsky doesn't seem to value much. But hey, he's another warm body, and I'm never against the Reds acquiring young pitchers with good performance histories.
Anyway, I'll take a closer look at these guys when I get back. But my initial impressions are that this is a pretty reasonable trade--Hamilton's an outstanding talent, and the safe guess (given that he's a position player) is that he'll outperform both of the Reds' new pitchers. But at the same time, he's not without substantial risk (injury and drug abuse histories), and the Reds are getting a young pitcher with good upside who is probably major league ready. Oh, and another pitcher with good minor league numbers. This addresses a need of the Reds, they're dealing from a position at which they have depth, and it has the potential for a great payoff. So initially, as much as I hate to lose Hamilton--especially a year before Griffey and Dunn may walk--I pretty positive about this trade.