Xenoblade, no contest. The combat system was more refined, the locales were far more impressive (and more vertical, which I really love), and the story was just so much more engaging.
Look, I didn't hate FF12, and actually I thought it was a good exercise for S-E at the time, to try and break free of melodrama, but what was left was a game that was very impersonal and kind of empty. Unfortunately, it failed as an exercise, as FF13 went berserk in the bad-melodrama territory. Also, FF12 was the most uninteresting soundtrack in the series, hands down. Not a fan of the music. Xenoblade may have not had a Uematsu or Hamouzu-level soundtrack, but at least it did more than conservative, uninspired, orchestral background music (grrr!).
For the time I played Xenogears, it took center stage in my life. It also happened to be one of those few games like Okami that I ended up pausing for a few weeks to play other games (in Okami's case, ironically, FF12!) but came back to as if I'd never left. Many times, when I stop playing a game for another game, I never end up coming back. But after my brief interlude with Skyward Sword, I couldn't wait to come back! And re-entered the game world without any problems at all.
