I wouldn't judge a guy for riding a step through frame or mixte, but probably wouldn't do it myself. First, I think the design, from an efficiency and weight stand point, is less ideal than a diamond frame. I don;t wear skirts, so there is no advantage for me. Second - I just think I'd look silly on one. When I see a dude on a step through I typically think it's either stolen or a hand-me-down/loaner and he doesn't want to buy his own bike.

There are some people on here who like step throughs/mixtes because they have physical problems getting over a diamond frame - and if it helps them ride, I'm all for it!