It's amazing just how visually impressive the show is. If it was done with the best we had 30 years ago it still would have been good, but the vfx would have dragged it down. Now it raises it to a whole other level.
I'd say it's a bad adaptation of the book. But as a sci-fi series, it's quite good. I rate it at least 7 out of 10. Although I haven't watched the second season because I'm waiting for it to be finished so I can binge it if I wanted to.
The show is based on the universe and some characters created by Asimov but it's freely adapted. You'll have to see the TV shows and the books as two entities, there are a few similarities, Easter eggs, etc. But they're different and both great IF you're not looking for a translation from text to screen.
The TV series is eerily beautiful, the story is better in S2 and more complex. Great cast too and on a "small" budget.
The way I see the TV show is like the creators are constantly placing details to say "Hey! This Asimov guy was really smart and he wrote this rad SF saga, you should really check it out!".
David Goyer and his team, they're not just making a show about some old scifi books : they're truly fans of Asimov's work and you can feel it. It's a work of love.
The original book spends almost no time with the old empire. Once the Foundation is established, the details of the empire’s fall are irrelevant to the story. In fact, the premise makes a point that the exact details of its fall don’t really matter.
I actually really like the show, but I've just decided to act as though it's completely unrelated to the books, because besides the names of characters, and the initial events, it basically is.