I give this a 10/10 because i cant imagine how it could be made better and still entertain kids AND adults.
I read some of the other reviews here and the most what i wanna say is already said so i am just gonna point out some things about the amazing characters in this fucking amazing show.
AND Yes SPOILER ALART
When i recently watched the show a second time i just fucking adored every scene where azual was in. When she first appears she is just a villian who seems like she is just evil and cruel. She never does something stupid in the second season and she never does something which doesnt fit to her. She is always winning the situation and it makes so much fun watching her just being herself. Though later on in the third season she changes, or maybe you could call it she Progresses in some kind of way, we already got to know her better through flashbacks from soku and spread information but when it all come to the end, the character just makes the next logical step and she gets just freaking insane.
But befor that we have one of the, in my opionion, best episodes from season 3, "the beach" episode. This Episodes kinda shows us how it could be if there would never have been a war or would it would be like if they werent the freaking children of the firelord, speaking of soku and azula at this point. In this episode they kinda seem to like each other and they look like they are really brother and sister. and you almost which like soku would just stay on their side, because it some kind of way it fits and it some kind of way you want that to see more of that. At least i wanted. With a love for realistic and cruel fantasy/scify storys i would have also liked a bad ending of all of this, of course it would make you cry even more at the end, but how freaking cool would it have it been if just soku and azula stand beside ozai over the burned Country of the earthkingdom? dont tell me that wouldnt be kinda awesome.
But back to her character progression, she gets insane. Not like fire lord ozai, who seems confident in what he is doing until the end, she turns from a logicial though radically thinking person to shadow of herself, just lead by misstrust and fear that she could loose her power or get betrayed again. Of course caused by the betray of ty lee and mai. And this logical progression just made me adore her even more, it makes so much sense, she always has been mentaly unstable and after she got betrayed by the only persons who, she thought, she could trust, she gets driven insane by misstrust and fear. I still shivers me thinking of the scene when katara ties her and she just screams and crys and laughs.