I have a friend who has a baby face. He works as a teacher, so he finds that his mustache and beard give him a more authoritative look. I also know a lot of men who wear facial hair, and as long as it's neat and trimmed, it makes them look mature and distinguished. However, I have never seen a man who didn't look better without the facial hair, even when it was neat and distinguished-looking. My husband knows that he is never allowed to grow facial hair except for those times of the year when Jewish tradition calls for it. What can I say? His face is too handsome to hide behind facial hair.
I think it totally depends on the man -- and I have known a man who looked great with a beard and not quite as great without it -- which is why he always kept one. I also have a male teacher friend, Machazait, who does exactly the same thing (and it's the same reason I wear heels and dress pants in the classroom when I teach). So, I suppose it can be situational, like any other style choice . . . good topic!
The key for me is that whatever the facial hair choice, it's kept up -- meaning trimmed and neat -- not a scraggly mess.
Aesthetically, I think I'd really enjoy having a full beard, like Alan Moore or Odin. However, three things get in the way of that. First of all, My facial hair can get neither thick enough nor long enough to look like I want. Secondly, the sensation of having hair on my face, especially in the mustache ares, kinda bugs me. Drinking from any sort of bottle while I have a mustache just creeps me out. Third, girls don't dig facial hair (with the exception of when it's part of a Jack Sparrow halloween costume, but I doubt I'll be able to do that again any time soon).
Twenty plus years married to a military guy...definitely not used to much hair, anywhere! A nice moustache can help a very young looking man appear a more mature, and I have to say I even like soul patches on 20 or 30 somethings.
There was a friend of mine in college who first had a goatee, then a full mustache and beard. It was all neat and trimmed, and he looked fine. Then, at one point, he shaved it all off. I did a double-take, and the first thing I said was "Ohmigosh, you have a face!"
There's a man in my synagogue, married with seven children. As long as I've known him, he's had a full beard and mustache, and he looks very distinguished. Then, I was once in his home, and I saw a photo of him and his wife at their wedding. He was clean shaven, and I couldn't believe how handsome he was.
I think that as long as the facial hair is neat and trimmed, it can look very good, but I still prefer a clean face.