A review from someone who isn't biased towards ATLA:
this was a very good show! it obviously differs from ATLA like each season has its own conflict to be solved. you will find a lot less fillers than in ATLA. don't watch this show if you're going to immediately compare it to ATLA, or if you want to know what happened to the Aang Gang. Season 2 was kind of weird in my opinion, but season 1 and 3 were super good! Team avatar wasn't as interesting as in ATLA character-wise, but it's a super good show. Go into the show expecting to like it, not with a closed-off POV!
This show is in the same universe, but it's still a different series. **This show is not about Aang, Sokka, Toph, and Katara anymore.**