Ok, my turn.
FFIX is the worst FF out of VII, VIII, IX, and X --BUT-- it's still one of my favorite games, because it's a FF. Just because it's worse than the others doesn't make it a terrible game. it's 3 major downfalls were the graphics, the characters, and the way the storyline played out.
Graphics: They tried to pound way too much into the Playstation. The result: overly pixelated, overly animated, slow moving (at least in battles) characters. FFVIII went a bit over the top, too, but not as much. I think VII's was just fine, no matter how lego-like they looked.
Characters: An FF game minus Tetsuya Nomura equals a terrible game. Unless it's an old FF where character design didn't matter too much since you're only 10 pixels wide. He didn't design the characters for IX. If he did, who knows how much better this game would be. You have a fat white blob with flowers for eyes and a pitchfork. A Buzz Lightyear in armor. A blue dude with massive red hair covering his eyes. And characters with tails that look equally male and female. Now, I do understand that going with the story they were created and didn't need to reproduce so they're neither. But still it's a pretty dumb excuse to be running around chasing after a guy in a bikini.
Storyline: I have nothing too harsh to say about the story. It just waited until the last 2 hours of the game to tell you anything. Too simple.
There are of course things about it that is better than some other FF's. I think the chocobo sidequest was one of the best. Tied with FFVII's. But IT DIDN'T HAVE WEAPONS (I mean monster weapons you fight, like Ultima, Omega, Diamond, etc.)!!
overall FFIX is a pretty fun game and enjoyable, but it lacks much of what makes FFVII what it is.