No contest XII all the way. XIII is a interactive cutscene, the parts you do play are so linear you may have just carried on with the cutscene. Autobattle and AI controlled characters that are missing the "I" (intelligence) only add to the shit.
XII was at least a decent FF, it was non linear and had exploration, the way an RPG should. People moan about the gambits doing the fighting for them but you all realise you don't have to use them right? You can have full control if you choose.