I stopped caring about the show after season 5 so except for the ending and some select scenes it's all I've really seen.
You'd have to have read the books to notice the shift in writing quality. What made AOIAF books unique was how GRRM build the world through the eyes/perspectives of characters. Season 1 especially, every scene had this invisible layer that you could only see if you'd read the chapter and heard the thoughts of the person whose perspective it was told from.
Season 4 onward diverted heavily from this as they introduced more and more non-canon material.
As someone who pre-ordered his hardcovers as they came out... I'm very spiteful towards GRRM for not finishing the books and think Game of Ed Sheeran is the legacy he deserves after selling out so blatantly.