I dunno. I think all the girls are suitably hot. Part of it is the dark environments they are found in so the shading may highight different features of the face, for a "mannish" overtone. Part of it is sexy perma-frown is not sexy. Part of it is, they aren't on all fours, sexily staring at the camera with a "come eff me" look so some might consider them "mannish" due to this.
I figure if you guys are focusing so much on their faces, you aren't watching the fist being put into it.