I finished reading this last week. As far as ratings go, I'll give the author brownie points for creativity. Haddon wrote with a unique style and "perspective". Overall, I didn't really care for it. It wasn't realistic, though the writing seemed to assume that stance. It reminded me of the movie "The Truman Show". I also didn't like the fact that there wasn't much meat to it. It was a brainless read, which is a good at times, but nah. So to end on the positive note, I'll give it the brownie points for the creativity and it was easy to read through with with a medium level of interest.
I picked up this book today and read the first short story. It was definitely a good read and requires rereading for analysis. I love good short stories.