It had a lot of action and interesting plot twists. My problem with this whole series was the inconsistency of the characters... And also that Mr. Colfer seems to think "strong female character" means "kickass chicks" instead of "well-written female character". There's a lot of casual misogyny, which I find even worse than straight-out blatant misogyny for being so subtle you almost internalize it.
Other than that, he does write in an interesting way that keeps you turning the pages, and his universe is interesting. It's a shame he seems to think the answer to sexism is female characters who despise other female characters for being too feminine.