I'll throw in one idea for anyone in favor of shaving: It was brutally hot and humid when I rode across Kansas. Previous experience with a beard always had me shave it off about March, because the beard was too hot. I was glad to be shaving when I had to cut the riding short every day when the heat index got too high, and it would have taken me even longer to get across Kansas if I'd had to stop an hour earlier every day.

Also, it's easier to apply sunscreen evenly if there's not hair in the way.

But honestly, that's mostly a rationalization for why I like to stay shaven. (As most of the reasons on the other side seem to be, as well.) Do what you want.