As someone else mentioned in their review, this is exactly the kind of book I used to think "Mum would kill me if she caught me reading this!"
And it's exactly the kind of book I'd love my kids to read (which is actually what made me think of it - I'm digging up books to recommend to them.)
I remember it as a violent modern urban take on the Lost Boys (the originals, not the 80's vampires), and it honestly scared the heck out of me as a kid, but again, like someone else said, I spent half my teenage years wishing I could run away and be a borrible.
It's solidly written, tightly paced and just the right urban fantasy mixture of familiar and alien at the same time. Highly recommended, for kids who can handle a little violence and characters that are far from black and white.