It's not so much that it sucks, but it's definitely overrated. It's far from the best Final Fantasy, or even the best PSX Final Fantasy. I especially didn't fact that so little attention is drawn to the fact that you are TERRORISTS. Only Johnny and Rufus really mention it, as I recall, and Rufus is just looking for an excuse to off you on live TV.
I think Rufus and the Turks were great villains, though, and it's a shame they were wasted on such a crappy party. Cid's the only really good party member. Nanaki's ok, and Vincent or Yuffie could have been good if developed more. I'm still not sure on Cait Sith. Reeve is an interesting character, but his Cait Sith persona is rather annoying. Plus, why did he care so much about being crushed?