This book was okay. It wasn't terribly bad, but it wasn't great either and yes, I feel as though the movie would probably be better. I didn't feel as though this book was as effective as it could've been - this was just so bland. The characters were flat, they could've been so much better developed. I didn't feel much towards anything, really. I think that the idea is good but to me, I kept feeling as though I'd missed out on things - the book could've easily been double the length. The lack of ending wasn't as bad as I had anticipated, but I'm annoyed that we never actually got to find out who the wolf was and things haven't been rounded up. I feel as though another book, if not a series, is needed to complete and improve upon this.
EDIT - Now I've read the 'bonus chapter', I do feel a bit better about the book. The ending was reasonably good, but far too predictable - I predicted the wolf to be who it was almost from the beginning and the consequences weren't surprising, either.