I have read many of Koontz's books, and I just don't see what the fascination is with this title. One of the things I have always liked about Dean Koontz is his ability to write a supernatural tale that is somewhat possible. There is always that feeling, however much of a reach it may be, that this could feasibly happen.
Here you have a tale about the Anti-Christ that starts off intriguing, and just degenerates into one long chase sequence. I think the last 150 pages or so is Koontz's over-winded description of the cultists trying to chase Joey and his Mom through the woods. Koontz never really explored the idea of is this kid really the Anti-Christ? We are supposed to think that because Grace Spivey is so intense in her beliefs that this kid may just be the devil's son? It would have been nice if Koontz had teased us with some unbelieveable or unexplainable manifestations of power from the boy, however slight, to keep us guessing.
It's like Koontz had a good idea when he started, but had no idea how to finish it. I was quite bored at the end, and was skimming the last 100 or so pages just to find out what happened in the end, which was pretty much nothing.
If you want a good Koontz book, read Intensity, Whispers or Dark Rivers of the Heart.