While I hate the vampire business, I had to pick Jubilee. Sure, she's the second fireworks-spouting young mutant girl named Jubilee, but she's been pretty great over the years.
Armor, on the other hand, despite having an amazing visual, is like, the *fourth* mutant force-field exo-skeleton girl, following boring ones like Skids and much more interesting ones like Unuscione and Cecelia Reyes. At a certain point, I just don't care about the latest version of a common powerset, like Tempus (fifth, six, seventh? time-manipulator) or the Stepford Cuckoos (like they needed *more* telepaths in that mansion...). What could have pulled Hisako out of that if she'd had an interesting personality, and... she didn't.
So Jubilee wins for me, because even without her powers, she's an interesting character.