I sport a ZZ top beard, but I'm not in PC, if PC allowed beards I would not expect them to let me keep it like this. There is a neat and clean beard, but mine isn't it. The clean shaven bit is a bit outdated, but it's much easier to enforce for professionalism. One might say a beard of 1 inch even cut is fine and professional, and another could say 4 inches a little rough is ok.
Personally I think just a mustache does not work for 90% of men, but I understand expanding what the standard is becomes a little hairy.