Nah, not yet. I'm trying to do my part and wait for the official release, but I've come this close to caving several times already.
Everybody I talk to says it's great, so it's only a matter of time.
All of this is spoiler free then. The network has to be really optimistic about its reception, because I can't imagine what the budget is. Nothing even in the third season of TLA approaches the animation quality in the first couple episodes of Korra and some of the backdrops are breathtaking.
It also seems like they're operating on the idea of the maturation of the original target demographic too, so that's also a big plus. My early impression is that there is a good chance the new series will be better.