Keith Law has an Insider-Only analysis of the Berkman deal, and it's fairly complimentary:
Houston could easily have gotten nothing in this deal, but both guys coming back their way have some value.
Arm action is a train wreck, but he has power stuff, including a 92 to 94 mph fastball, a power curve in the low- to mid-80s and a hard change. On the right night, he'll show three above-average pitches.
Toolsy, athletic infielder without a clear position. He could end up in centerfield long term, but he is still very crude overall and his swing and body don't point to future power. He needs to learn to take a walk more than once every week and a half.
There's more, but I'm uncomfortable pulling too much stuff from a pay-article. Meanwhile, Jonathan Mayo drops some knowledge on us about the two:
Melancon is a hard worker with outstanding makeup, possessing the kind of aggressive mentality teams like to see in a short reliever. The Yankees had hoped he'd be a seventh- or eighth-inning guy for them, but he has the stuff and makeup to close. The one thing he needs to do is command his fastball better. He's been elevating too many of them, making them too hittable for Major League hitters. If he can command the lower part of the zone better, Houston could have a future closer on their hands.
He should hit for average in the future and many feel he'll grow into power as he matures. Plate discipline -- 18 walks in 99 games -- has been an issue, and it remains to be seen how much he can improve in that area of his game. He had arm surgery a while back, but he's 100 percent now and has a plus arm. In all likelihood, he'll have to use that arm in the outfield and could have the tools to play either center or right. His hands and feet don't work well enough to stay in the middle infield, but with a plus run tool, plus arm and plus body, there's still plenty to like about this high-ceiling prospect.