Final Fantasy 10 by a bit.
To be honest, when I first played XII; it was a masterpiece. Then the battle system just threw me off, not only that I kinda grew tired of the game after finding some of the bosses who were difficult interesting (not down talking XII or anything.) I just find Final Fantasy games should either stay turn based or be like Crisis Core, but since XII took place in Ivalice then it had to have that game play of Tactics.
Final Fantasy X was not that great of a game, but the characters (which only 3 characters were worth keeping in party and using.) The battle system was eh, and the sphere grid made the game leveling up bland.
In all honesty, I'm neutral on this one.