I liked this book, but it was not easy for me to finish it. Sure, the mythology was fantastic (the spin she does on angels, demons, vampires, werewolves, etc.) but through no fault of hers, I had to put the book down for a while. Young Adult and even adult urban fantasy (or fiction if you will) is bulging with those above stated supernatural forces. However, Cassandra Clare is just different enough to make this a very enjoyable ride. There are unexpected twists and turns and beautiful world-building involved in the book. I was even surprised by one twist and books seldom surprise me anymore.
All in all, this was a good book, and I plan on reading the sequels soon.