"Horror" is perhaps the most misused genre label. For whatever reason, horror is a blanket term, and has the misconception that it must be all hack-n-slash and gorefest. People tend to think that Horror is light on character, must have killer animals that rise from the grave to eat your face, and must involve all manner of shock-value elements.
Pretend that Dan's book is Urban Fantasy (here is a secret, Horror and Urban Fantasy are the same thing). Dan's book has all sorts of character development, plenty of suspense, humor, and terrific pacing. Over at the EBR blog, we just updated our review due to the US release coming shortly. Go give it a read.
My wife hates "horror" and she thought Serial Killer was full of awesome, and made me import the sequel (which I was gonna do anyway). Think of it as a young Dexter, only much better written, and with borderline paranormal aspects in it.
I haven't seen any sample chapters lately, but im sure Amazon will have some up close to the release date. Also, if you are unsure, just wait until it is released, go to you local bookstore, and read the first chapter or two.