I didn't think Squall would be any good, but at least as a beginner character (I did his story early to get it over with) he's pretty decent. I'm also surprised at how much fun it is playing Exdeath. I mean, I hate the block-attack style of play in most situations (I have every character's guard ability unequipped) but for some reason I find playing as him really satisfying.
On the other end of the spectrum, I was overall disappointed with Bartz's meager selection of moves.