100% the story, PR and marriage side-quests, getting all monsters and their oversouled versions, paying off O'aka's debt, etc and then there's the Last Mission as well.
My suggestion is that you keep the vita version.
None of those things are really a grind, though. Well, except the monster thing that I never bothered with because I don't care. The only thing that's kind of a grind is digging up machine parts in Bikanel Desert, and that's not nearly as bad as the FFX stuff like filling the sphere grid and Blitzball.
You can pay off O'aka's debt in like a minute with some luck in the Guadosalam data exchange.
Oh and seeing the paths on the sphere grid is a bitch on the vita.
Yeah, I had to look really closely at the screen. It was a bit weird.