OH has read and loves the books, he gets all nitpicking about the changes in the show, i do intend to read them but i've got a huge pile of books to get through,
I jumped on the bandwagon after season 2, and decided to read the books first. And honestly, I was really pleased with how minor the changes seem. They even do a good job of adding extra scenes. maybe it's because the author is really involved with it.