I like this book a lot, both because of the plot and because of the heroine's spunk and "special situation". Avoiding spoilers, I'll say that the authors do a good job of capturing the feelings of somebody in her situation. The action is fast-paced, entertaining, and believable. The characterization, while not going into great depth for most anybody other than Celia, was believable throughout. The bad monsters are definitely treated as monsters, though; not much nuance in their representation or in Celia's view of them.

One thing I'd change (again avoiding spoilers): most of the last chapter sets up the conflict in the next book. I think it would have been better to have left it out of this one and opened the next book with it. But I admit I'll certainly pick up said book when it comes out. :-)