Not bad... that's about the nicest thing I can say about this book. The book has wonderful application to the Christian, considering Demons and Angels are talked about openly and from a Christian worldview no less, but it is rather simplistic in its character development. The plot is very simple and has no significant twists, and is almost completely obvious just a few chapters into the book. Usually your guess on what will happen isn't right, and thus it makes the book interesting; in this book, your guess is right. The first time you guess.
After having read many secular fantasy novels, this one doesn't stand up, though it finds a place on my shelf thanks to its strong Christian thematic. Simple, but an entertaining read from the Kindle on the way home from work every day.