I was flipping through Cosmo and there was a little blurb on their Beauty Q&A about concealer for men. They said that "there are a lot of dude-friendly options now" and my curiousity was piqued.

They suggested Clinique's Skin Supplies for Men as a good option if a man is looking for concealer, siting it's "masculine packaging" as a good way for him not to feel too embarrassed. I, of course, thinks it looks like a good nude lipstick....so as far as the masculine part goes, I'm not too sure.
So I googled "concealer for men" and found The Men Pen which I like for the name alone and John Varvatos has a Makeup for Men line with a concealer that looks "manliest" of all to me. All of these concealers are appealing to men who want to cover up breakouts, razor burn, under eye circles, and the like. I'm all for a man concealing skin issues but I want to hear what you think:
If you're a man:
Would you use concealer?
If you're a woman:
Would it bother you if a man used concealer?