Final Fantasy IX is one of my favourite FF games, so my opinion is pretty clear.

To be fair, though, I haven't finished FFXII yet. I managed to play maybe 36 hours of it, before stopping (for an unknown reason) - that was over a year ago.
I've been intending to start a new Final Fantasy XII file for a long time now, and finally did it the other day.

Actually, I have this thing where I never finish a Final Fantasy game on the first playthrough. I always tend to stop playing it at one point, before finally picking up the game again later to yet again play it from the start - this time more thoroughly and extensively. It's almost like I'm half-assing it on the first playthrough, subconsciously knowing that I'll finish it at another point. Strange.