This winter is the first time I actuallly grew out my beard and I was almost startled by the power of it. Instantly people started calling me "Sir", started acknowledging me more in the workplace, seemingly shaking my hand differently, I received more flirtation, and all joking aside people seemed to pay more attention to what I was saying. And yes, it's made me look "manlier" in the gym (but of course I'm the same person just bearded).
A little beard goes a long way.
One draw back is feeling the moustache pressing back against my face when I kiss. The second drawback is it covers a lot of my handsome mug.
+1 to OMAC.
Now my reasons:
Because I can.
I like the way it looks and feels.
Grew a beard last winter for a work beard contest, took second place when I plastered my newly bearded face on a picture of Al Borland on the set of Tool Time.
Started again this winter and have gotten some positive feedback. I think the keys to the beard are keeping it trimmed, still shaving the neck, and being able to admit defeat if you can't grow a non-patchy beard.