I just finished season 2, it's such a good show, last air bender original series vibe, with that 2d/3d animated art style. Season 1 had some choppy scenes with slower movement but that seems to have been mostly addressed in season 2, but the art style looks great to me.
9 episodes per season, but short duration so each season is kind of like a 3 hour animated movie. Still, very well done, and they dropped season 2 in what seems like 6 months or less since season 1 aired, if they can keep that cadence up, we will get to see more without waiting too long.