I really love the story and read the books just before watching the shows. The shows actually follow along with the books fairly well, but of course, not exactly. The books end just before the "Battle of the Bastards", so the HBO writers pretty much had to start making up their own story lines without anymore George Martin books as guidelines (although I did hear GM helped them some). That's where I started having problems with the show. It was still entertaining, but I just felt the characters started straying away from their earlier personalities. One example was I really felt Tyrion starting getting weak and timid and not his usual bold, smart ass self.
I enjoyed the final two seasons, but I wished George Martin would've finished the stories himself so we'd know "what really happened".
Really great epic story though. Right up there with LOTR for me.