Oh, boy, where to start?
First off, I guess I should say that one of the reasons I enjoyed this more than the first book is because I already knew all the characters and didn't have to keep flipping back to the character list for a reminder of who they were.
Aside from that, I don't know... Everything that was good in book 1 seemed better in this--the action, the characters, the gritty tone of the story, the plot. That one scene of the rescue mission? I literally could not stop reading until I'd gotten through it. (The fact that it involved a couple of my favorite characters may also have had something to do with it.