I think Ling's Pi Gua Quan is not as, how do I describe it, "pronounced" as Helena's. That and she uses Baguazhang as well.
I love Ling, but her's doesn't feel as elegant as Helena's for sure. I thought Helena was kinda awkward in DoA2 (prolly cause of Ling) at first, but TN did a really good job making it look natural for her.