I would have liked this book more if we didn't learn so early on who the killer really was. I did like the mystery of not knowing why Jack blamed Cameron for him almost losing his job three years before. That's explained fairly early on, but if it hadn't been explained to us (the readers) until Jack learned why I think I would have been driven crazy wondering. I did find Jack's idea that it was all a prank at first really funny, but I can't really see anyone doing a prank like that.
I ended up liking Jack and Cameron together, although the UST was kind of annoying when they still hated each other. It became less annoying after Cameron told Jack what had really happened three years before.
I just realized this, but it's kind of funny that I finished the first book in this series today, since book five came out today. Not planned, really!