The show writers add a lot of additional content that isn’t in the books, especially pertaining to characters. Almost none of the character stories are from Asimov, because the books are focused on events over thousands of years, not on characters. The content the show writers add isn’t very compelling or interesting.
The books themselves aren’t all that great. They’re okay. They were probably pretty revolutionary in their time, but they’re just okay now. I think they’re worth reading as important pieces of sci-fi history, but don’t expect anything mind blowing.
Basically I’m saying it doesn’t matter if you read the books or watch the show. Both are okay, but the show is a lot more boring than the books. Some people probably love the content, I could take it or leave it. For the books I took it to the end, for the show I left it after a couple of episodes.