Just finished this and found it one of the most enjoyable Predator novels I've read.
The Predator himself was absolutely brutal, every scene featuring it was a proper treat. The Reaper characters were mostly well established, too.
Only slight gripe probably was the author's frequent use of the word "hell" as an exclamation in sentences from most of the characters, which feels as if it's one of the author's own particular well used expressions that has seeped into the writing, but otherwise excellent and a real appetite whetter for the film.