Oh god, that's a tough one... I would have to go with VP1 over 2 though. Mainly because I liked how each character got an exposition instead of a 2 paragraph blurb buried within the status screen, and VP2's plot seems like a really confusing, half-assed way to shoehorn a bunch of VP1 fanservice into the game, not to mention that for 75% of the game (chapter 3), absolutely nothing happens, plot-wise.