I will say that I will be watching it.
It's surprisingly mature for being on Nick, whose kiddie nature tends to make you cringe at the idea of actually liking one of their shows. Avatar actually grew on me as it went on, and became more involved and the characters became more interesting. (there's a lot of characters to focus on too, which is nice)
The animation for the fight scenes is some of the best I've seen in a while. It's very fluid, which usually you don't see as often, or when you do it astounds you because you're not used to seeing it.