I didn't think Legend of Korra was very good...at least, not until the last handful of episodes, which were amazing and pretty much equal to the original series' first season finale. Other than that, the only bits I enjoyed were the flashbacks to the characters from the original series (especially when they involved Toph. I fucking love Toph). Hopefully it further follows in its predecessor's footsteps, as in it continues getting better and retains a consistently high level of quality in the coming seasons.
What I didn't enjoy at all was that there's a pretty big focus on "pro-bending" for several episodes and I just found it utterly dull. It feels like very, very little happens until midway through the season, then it gradually becomes better until the plot finally reaches the point where it's engaging (at least to me) and makes you want to keep watching. I haven't watched any of the episodes since they originally aired though, so my assessments might be a little off. Another major gripe I have with it is that most of the characters feel like much lesser versions of characters from The Last Airbender; Bolin is a retread of Sokka, Mako sucked up all of Zuko's angst, a female character whose name escapes me actually looks a lot like June and of course Naga and the "fire ferret" (which looks just like a red panda) are replacements for Appa and Momo, respectively. It's quite a shame, since the characters who do have their own distinct personalities are infinitely more appealing, including Korra herself. In fact every time Bolin's on-screen, it just makes me miss Sokka. Oh, and one more thing that bugs me: There are still sky bison. You might recall that Appa was the last one. Well, the creators just decided to repopulate them with absolutely no explanation. Now it was actually supposed to turn out that Appa was female and pregnant over the entire course of The Last Airbender, but they scrapped that idea and as far as I know Appa is still canonically male, so...that really bothers me for some reason.
Nevertheless, I'd say Legend of Korra is worth checking out. It's still a decent show and I've been excited for the second season to air since it picked up.