I've read the Tithe trilogy and that was interesting. Actually, after i finished reading each of the Tithe books, i was blown away. But this book was okay. It wasn't that of an original concept - of course it was a new idea but i thought the concepts weren't explored enough, there wasn't enough background, enough history. I always enjoy when an author goes deep into the new idea - where it came from and all that. But here, information was given once in a while and when i was done reading, i was relieved i finished and could move on. I felt sorry for the main character, not going to say why since this will spoil it for you. I'm not sure i will read the next one, if one is to come out.
I think after the Tithe trilogy i was expecting something similar - something very original but i didnt find it here.