A beard looks good or bad depending on the wearer. I'm not just talking about looking 'sexy' as this depends on the guy being good looking as well, I mean whether it looks stylish or cringeworthy.
Regardless of how good looking he is, a fashionable guy with a good dress sense and well groomed (including keeping the beard well styled and tidy) is likely to be able to pull off a beard well. But a nerdy guy trying to grow a beard to look more manly or rugged, will look bad. A dull middle aged guy that otherwise has a boring image, will end up looking like an OU professor with a beard.
Age has something to do with it too. Guys aged under 23 rarely look good with a beard. Late 20s and over it can look good.
Without a beard, Aragorn would have only been able to kick 10% as much arse as he did. If Legolas had had a beard, he would have been able to fire an arrow back in time and do away with Sauron before he'd even made the rings. Fact.