Not that anyone asked for my opinion, but as someone who grew up watching the cartoons, I was really hesitant to watch the live action. I'm glad I did, though - I had fun reliving the nostalgia!
Without spoiling anything, and because I want to focus on the positive, the things I really enjoyed - The music, the scenery (gorgeous!) and the twists they added into this series.
The actors for Prince Zuko, Zhao and Sokka were spot on! Especially Zuko - he was a really good balance between bitter and living in the past, and anxious teenager. He was the character I identified the most with growing up, and the character I still identified the most within the live action. That actor was amazing.
Another thing I really appreciated was the CGI, funny enough. The bending looked legit! And APPA AND MOMO WERE SO CUTE! I do wish we had more scenes with them, though.
I can't wait to see Zuko's character growth in the next series, and meet Toph. :)