It has been a while since I read any Dean Koontz. But this will not be listed as one of my favourites of his. It's... ok. The first half I found to be dragging out a bit. In the last 1/4 of the book the pace picked up quite a bit, but not enough to save the book in my opinion.
What made it better than it could have been was the narrator, he did a great job setting the mood and doing the voices of the different characters.
All in all an ok read, not one of Koontz' best work, but not a waste of your time either. I would highly recommend the audio book!