Some eggheads in marketing tested the impact of product endorsements from men with whiskers and men without. (Ah, the joys of working in academia.) Study guinea pigs rated the bearded men as more trustworthy and expert on everything but underpants... probably because resistance to shaving signals resistance to other fripperies of civilization... like underpants.
Reports Tom Bartlett:
The researchers say the implications of their findings could extend far beyond advertisements. For instance, male politicians might want to consider not shaving because the "presence of a beard on the face of candidates could boost their charisma, reliability, and above all their expertise as perceived by voters, with positive effects on voting intention" [Tom Bartlett, "The Trustworthiness of Beards," The Chronicle of Higher Education: Percolator, 2010.04.14].
The article doesn't appear to separate mustache and beard effects, so the safest bet for Chris Nelson, R. Blake Curd, and those other little shavers is to grow it all back!