I wasn't a fan of this one. I was bored most of the time. It isn't really my thing.
And I definitely didn't like being told that Clary and Jace were siblings after they had made out. And apparently (SERIES SPOILERS) they decide that they're okay with that in the next book?? Ew. Ew ew ew. But then it's all "okay" because in the third book they find out they aren't siblings after all. It's too late at that point; you've ruined that relationship for me. (END SERIES SPOILERS)