Damage wise, combo, EX’s and the rest
SA2 is better. Does better damage, is better for punishing somthing whiffed (although SA1 is good for this too, SA2 has better range), and is almost as good as SA1 for EX (you get one less EX move).
SA1 is still a good super IMO, comes out really fast (I dunno how many frames, but fast), works for AA, the afformentioned extra EX move (giving you the option to do the EX combo, which does more damage than the super), and combos well (although I think , I THINK that you can miss some of the hits of it if youre too far when you hit with the cr.MP. Someone please correct me if Im wrong, I dont use this super very often).
It comes down to damage and range IMO, and SA2 is the winner, even if not by much. Its a tough call Im betting that some will disagree, but I know most people prefer Brave Dance for the reasons I listed.
Im betting some of the more experienced Elena users will be able to discuss this in more detail. I havent been using her for very long, and she isnt my primary character. But yeah, SA2 is better IMO.
…and then of course there’s Healing, which IMO is one of the coolest supers in the game:p