Don't know how to rate this. In the beginning I really didn't like Jason very much. Although I could relate to his behavior as the story moved on and I felt sorry for him, for me he still wasn't a likable character. The writing was very good, but for the book being amazing, the topic was just too heavy for me. Might be my mood today. So I think I'll go with 4 stars.
ETA: Just saw that there is a sequel coming in February. I will definitely read that. I'll just have to wait for the right frame of mind:)