I really wanted to like this book. It has a great premise (as far as zombie-ish horror books go). There are a subset of genetically different people, who one day "snap" and become "Haters." They run amok and strike with an amazing amount of violence and relentlessness. The potential for paranoia and fun with epidemiology of violence were there, but it pretty much falls flat on its face.
The main character (I am loathe to use the term "protagonist") is just a slug of a human being. I can't get how his life has really changed or how he is "losing" anything when he spends the vast majority of the book bitching and moaning about his job/wife/kids/money issues/father-in-law/etc. I can't even bring myself to dislike him, I just don't care and want him to go away (I read on, hoping something bad would happen to him).
The writing was incredibly monotonous (20 or 30 pages swaths of "my life is awful" followed by a couple of pages of random violence, rinse, repeat) and felt very unpolished (and not in a good way).
Beyond that, the book seems to revel in its violence and bloodshed, so if you are looking for violence porn, it's the way to go. Then again, if you want cohesive plot, some kind of development, good characterization, and something better than what a 12 year old bully would like to read about, just skip it.