Viper, meet Vanessa's fists. Fists, meet face. In the end, Viper will take this. Not only does she have the aerial advantage thanks to her suit giving her flight (as seen in the infamous Cammy vs. C. Viper scene in the SF IV OVA), but she also has electrical and pyrokinetic skills that would easily knock Vanessa on her butt. I'd say Viper wins if she plays if smart.