I'm a sucker for vampire lit. Always have been. Was completely tickled by the whole Mercy bit (I've known about Mercy for ages---Food for the Dead is a great book). I saw someone say somewhere that this is not a vampire novel. Hard disagree. There are different types of vampires in the lore. I loved this book
On a more personal note, the description of scoliosis surgery is spot-on. I had it done when I was 16. Oh, the memories.