I really liked the Cinder Spires, but I'm hoping for a tighter focus in the next book. Some of the characterization felt a little forced to me; the only protagonists who felt natural were Gwen, Grim, and Rowl. The others just kinda felt stilted, like...well, like characters in a book. I felt similarly during the first entry to the Codex Alera, which (in my opinion) figured out what it was during the second book.
I still liked it, and it's mandatory reading on my Annual Butcher Reread, don't get me wrong. But... anyone here ever read Dracula? You know how some of the characters kinda just say things, and you roll with it because of the format of the book, but some of them never feel like people? Like Lucy and Quincy, to me. That's kinda the same note that struck me with some of the characters.
Liked the plot, liked the world that was being built (the highlight, for me), liked the mechanics, and generally liked the characters, but I want more from the next entry.