I used to wear makeup, like, full on makeup, mostly foundation, eyeliner, bronzer, mascara and lipgloss. There was a sort of direct split, people were either freaked out by it and thought it was disgusting or they loved it, really loved it. There was a small group of people who didn't care either way, that group grew in numeracy over the 3 years I did it. I have a beard now, so I stopped wearing makeup, 'cos you can't really have both.
If you want, the other way around, it wouldn't bother me that much if girls started growing beards, ahaha.
Yes, though it depends on the type of guy. Metro guys might wear makeup, then you get gay guys and guys who want to be girls. In those cases I think its fine. I personally, probably wouldn't date a guy that wore makeup, only because I'm not extremely girlie myself, so it would probably make him a bit more feminine then me, and I'd feel sort of weird with him. I do wear makeup, but if a guy I dated wore more than me, I'd sort of be put off. Plus I think guys are meant to be sort of rugged and imperfect, that's what makes them sexy.
Call me the old-fashioned, stereotyped broad but no. Unless you're on camera, just don't. I don't care how bad your acne is--wash your face. If a guy I liked told me he wore eyeliner or something, honestly, I would just consider him as a friend after that. That's just...no. Too fem for my liking.