(NOTE: despite matching ISBNs, the edition I own was published by Abbadon Books and has a different cover.)
It was okay. On the plus side, a descriptive style that actually made zombies on their own creepy again (which is pretty rare; usually I find it's what they do, or what people do in reaction to them, that's the source of chills), and a fast-moving plot. I am not up on medieval siege weaponry, and I never got bored or felt I was being told something irrelevant.
Downsides: found the gore to get a bit overbearing after a while, and the pacing sometimes feels choppy.