I like Paine's one-dimensionality. Her story doesn't really add squat. You get the impression she would more or less be the same even if she wasn't involved in the whole Crimson Squad incident.

It's like SE knew they didn't have to try.

Rikku in FFX had a lot more depth compared to X-2. She was also dressed better and had tasteful hair.

So probably Paine for me.