I don't have much to say, but...
When I start watching this, at first I thought it was childish. I don't know what to watch, so I just continued. Later on, I thought this series is unique.
I mean, unlike most kid-friendly series, the characters did not always succeed on their first try or how they intended to. (Spoiler) Like when they try to enter Avatar Roku room and when they try to defeat Lord Ozai in the eclipse. The series is not always focused on the good guys only. The series also shows how the bad guys feel and why they do what they do. The minor characters are not usually forgotten by both the series and the fans.