Many people write this show off as a children's cartoon or generic fantasy anime.

That's a mistake.

You will laugh. You will cry. You'll get shivers down your spine and weight in your heart. And you might be a slightly different person by the end.

I've watched a good bit of TV, and as an adult in his 20s, this is still the only show I would give a 10/10. The worldbuilding is original and amazing. The animation, art and music is gorgeous. The plot is a standard but extremely well implemented hero's journey, and you'll be deeply connected to the characters well before the end. There's no Japanese anime weirdness, no overused clichés, an a nice mix of light humor and mature drama you wouldn't expect to see in a Nickelodeon cartoon of all things. And there's a truly amazing amount of detail in all of the show's content (As an example, the creators hired a real martial arts consultant to create/animate the different bending forms).

No show is perfect, but the only real complaint I have is the quality of the release. Avatar was produced/released in 4:3 480p, the DVD was poorly mastered, and Nickelodeon still hasn't released the amazing soundtrack.

Before you write this off as immature animation, do yourself a favor: get on Amazon Prime and watch it. Doesn't matter how old you are, bring your kids too. And don't give up after the first episode.

Also, it's worth nothing that this was NOT originally intended to be a Nickelodeon cartoon, they just happened to be the network to pick it up. So whatever your Nicktoon expectations are, don't expect them here.