This show is very good. I don't think it quite lives up to the care-free and spiritual energy that radiates so well from the original series, but it is good nonetheless. However, I would advise not showing to younger children. If your child is fairly young and mature enough to cope with the themes of the show, I would recommend it, it's well written. But if your child is sensitive to themes like violence and frightening imagery, I wouldn't suggest you let them watch it. It's more adult- like then the Last Airbender, and not just for cartoon violence. There is some scary imagery, like the use of "blood bending" is quite frightening, as it shows the characters veins pop out, and it has some sound effects that are cringy. The charecter Amon uses a technique to "remove" one's bending, which looks like he is draining the life force out of that person, not to mention he is an over-all creepy character. The second season has episodes about the comic relief, Bolin, starring in the first-age technology of "movers", (movies), with a young woman he works with giving some suggestive imagery that hints the theme of pornographic films. The relationships are complex, and there are multiple scenes of break ups and cheating, none of which would be seen in the original show. I would say the violence is the worst of it, though. In the season one finale, there is an emotional and disturbing scene where (SPOILERS) a man commits suicide and murder by blowing up the boat he is on with his own brother. In season three, the darkest of the seasons, we see the villan, zaheer, an airbender (which in the original show was supposed to be the good and harmless element used only by the main protagonist, a twelve year old, so this may be disturbing for those who grew up watching the first show). Zaheer uses his airbending to kill one of the minor characters in the season, and suck the oxygen out of her lungs, showing her eyes bulging, as she falls to the ground, dead. There is also a scene where a criminal man commits suicide to prevent from going back to prison, and another scene where a water bender gets electrocuted by one of the main characters, a "good guy", without second thought, and shows her scream bloody murder before she dies. There is a scene where korra, the main character, gets poison injected in her body and begins hallucinating disturbing imagery in a very dark scene. And the worst of it luckily got censored by nickolodion. One of the bad guys has the ability to shoot fire from her mind, resulting in an explosion, but a metal bending clamps a shard of metal around her head right as she shoots having the explosion go off in the metal, blowing up her head. This is very tamed and is very suddle, but it is implied, as you see her smoking body afterward.
Overall, it has good writing, excellent animation, a very good story, and a very good moral, as the main charecter, Korra, is portrayed as a hero, and it always has good lessons about learning, and what is good and what is evil, but I would advise not letting young or sensitive children be exposed to this show. Thank you.