I would say American because they appear more confident and enjoying during sex. Having said that , a lot of american pornstars have a wild persona in front of camera and sometimes they overdo it. But a lot of them give the real feel to porn unlike Euro babes who are simply blank faced and hardly seem to enjoy their work. Although Porn doesnt require much acting, pornstars can atleast act as if they're enjoying it, or take control of the scene. American pornstars are awesome in it. They really know how to act like sluts/whores on camera. I dont know abt European women, but Samantha Saint and Nicole Aniston are the two most beautiful and hottest women I've seen in my life,not just in porn.Its hard to imagine they're doing porn.But they're my favourite.And they're American.