It's alright. I didn't bother to watch it when it first aired, because I dislike young main characters. However as an adult I willingly chose to watch the entire series. I really enjoy shows with a map, different countries, different cultures and people. I also enjoyed the powers and fight scenes. I was a bit disappointed that he didn't show mastery of all elements by the end, and the ending was kind of abrupt imo. I enjoyed the overall themes as well.
I watched half of Korra, and I am saving the rest for a rainy day.