Although it's a very different Final Fantasy game, it works so well (as long as you like fighting games). The battle system actually feels very much like Kingdom Hearts, I think, though with a lot more freedom (you can literally stay in the air for the entire battle if you want, just keep dodge-jumping, or chasing).
I'm not a fan of fighting games, and I still love this game in more ways than I can describe. So much freedom, so much fun, so much customization, so many characters, so much good music!
I don't remember the last time I was so happy I bought a game. I had doubts, because FF games lately, although I love/like them all, have been changing and I haven't enjoyed them quite as much as I used to. But I'm glad I bought this for full price when it came out. Seriously one of the best spin-off titles for any game series ever, in my opinion.