It's been a while since I've seen it. In fact, I'm not sure if I'd even played a Final Fantasy game by the last time I saw it (without falling asleep at least). All I really remember is being annoyed by Steve Buscemi's character, being annoyed at the incredibly cheesy and over the top villain...but being absolutely astounded by the animation (which judging by the videos I saw on YouTube while looking for the trailer, haven't aged well).
I may have to try it again sometime. But usually a show/movie I thought used to be good turns out to be trash. Very rarely does the inverse happen.