The Legend of Korra starts pretty high paced and the new avatar is found fast, in contradiction to the previous series (where they take more time with the intro). This means that the adventure also start fast. Also, note that you should have seen the "Avatar, the Last Airbender" before you watch this one.
They have put some new concepts (for this series), like: after 70 years there is new some new technology, more love story, and a lot in the city (where Aang travels a lot over the entire world). I like this, but I have the feeling that there is a little too much, like too much new technology and too much love. I would have found it better that some technology is still being developed or missing (which other technology could be made clumsy in use). But there are also some new cool elements, such as the way of telling what has happened "previously on avatar", and a new sports game.
The humor is still good (I had a very good laugh somewhere in episode 10), and it's nice to see some of the previous (aged) characters back. I rate this 8/10 because of I really like the concept of newer technology in a fantasy world. But not higher because some elements are a little too much (to my opinion). Anyway, I couldn't stop watching and saw this entire season straight.