I had a hard time categorizing this one. In many ways, it's a literal urban fantasy -- a story that takes place in future Manhattan, which is powered by mystical energy. At the same time, it doesn't have any fantasy elements aside from the presence of said mystical energy, which seems to be more of a psychic trait than the presence of magic.
It borrows from Romeo and Juliet but plays around with some of the more tired tropes pervading a lot of YA lit. The romance was more interesting than I expected. There are legitimate reasons for the forbidden nature of the relationship in question, and though I am usually annoyed by Forbidden Love Because of Reasons, it worked.
I did become very frustrated with the narrator for a while, for the same reason I was yelling at Eona in Eon: Dragoneye Reborn. The answers were at times painfully obvious to the reader, but the narrator couldn't wrap her head around them until pretty late in the game. This is spectacularly annoying, but I enjoyed the story in spite of it.
This book was fun. It has futuristic mob bosses, divided cities, threats of revolution, some social commentary, an oppressed underclass, and a heroine who had begun to come into herself by the middle of the novel. I read it in one sitting while knitting, which was a great way to spend a morning.