well, in all fairness she did win the fight (with the sadist, although the one doing the killing blow was Hikawa). But then she was surprise-pwned by the aliens and after that she hasn't done much.

But her design is probably the best/most realistic, although it's not surprising considering that she's basically based off the actress who played Gogo in kill bill. Maybe if Oku ever comes back to Gantz he'll expand on the vampires, there's certainly a lot more that could be done with these 2