As a big fan of the original and subsequent novels, I am enjoying the series. If you haven't read the original books, don't bother, since they have little to do wit the series, however. Saying this is "based on" Asimov's novels is really more of a loose re-interpretation of the story. I can understand the major shifts though, it would be difficult to make a movie from the books, they span millennia and many character lifetimes.
The writers took many liberties that are somewhat annoying, changing sex of main characters bugs me. Having said that, combining several characters into one make a kind of sense from a production stand point. To follow the original would require a huge and confusing number of cast members.
The resulting series is dramatically different from Azimov's Foundation, but it stands on its own merits. Kudos to the writers for making a new and visually appealing production, and to the actors, producers, etc.