I never seen all of them, but I really liked the episodes I watched.
I certainly loved Korra though, and I really hope to see a new season of it. The last airbender was a great show though, really, I wish I'd seen all of it. I've even seen the last one when they defeated the fire nation. I certainly loved the jokes too! It was true work of art of a show, I must say.
The two shows were pretty good to me! :3