Yeah, thinking about it, there were few characters from a video game that I actually liked as a character as much as her, with only some of the Type Moon girls coming ahead of her. (I can't really count Patchouli in this, as I like her more for fanon than her actual canon.)
I hated Luca by the end of her Cosmosphere (especially after the point where she fantasizes executing Cocona for "getting too much attention" from her brother), and never really felt Cloche managed to stand out above the events of her background and her character archetype.
Jacqli/Mir was both the emotionally fragile little girl beset on all sides by forces beyond her control and the giant middle finger to the world for expecting her to break under all that sappy Freudian excuse nonsense at the same time. She was the only one who really could be a bitch the whole time, even being a bitch to the character that was supposed to be "me", and I would still sit there smirking, and cheering her on for doing it.
... reflecting on it more, I think, however, it's entirely personal. I remember getting into arguments with people who actually liked Luca when the game first came out. They said, "Oh, she's great, because she behaves like a real girl," and I responded, "Maybe, but when I meet real girls like that, I want nothing to do with them, either." Everything Luca did was just petty and driven by jealousy, and I just never came to be able to relate to her. Jacqli, meanwhile, she lived a life of extreme and unbelievable circumstances (so she likes walking around naked because she's spent the last 300-some-odd years naked plugged into a giant computer-tower subconsciously directing an entire city and a good portion of its residents...) but reacts to it in the way that I can actually relate to, in ways that I just couldn't come to like Luca or Cloche for.
Updated
Ayatane, I'm hungry.Yes, here's that PSP with MH you wanted.Ayatane, it's Mother's Day, so please give me a present.I didn't pick him, Croix picked me.I kind of get the feeling I chose the wrong girl.No, I definitely did.Leave it to me.You really picked a keeper, Mother.It's almost ready, so please wait just a little longer.Ayatane, this button fell off. Can you sew it back on?Sure, no problem.Ayatane, kill that, right away.*click click*