My phone still doesn't support it (and knowing Samsung, it probably never will) but from what I've seen so far in reviews and articles it's definitely worth it. Don't expect any major changes though, it's mostly just a bunch of performance and graphical updates.
Surely it would come out for the Galaxy Note 3 and Galaxy S4 though? Not all that optimistic at the chance of it being released for my ancient Galaxy S2 though, oh well. But yeah, I've heard its pretty good too but nothing groundbreaking really just small changes.