Well, I wouldn't be too happy, that's for damned sure! I consider myself lucky not to have to deal with periods. Besides, how fair would it be to make men deal with both menstruation and susceptibility to being kicked in the balls? (Further question: how would this work, exactly, physiologically speaking? Would this use an existing hole, or would a new one suddenly appear?)
But anyway...
If men had periods, they would constantly talk about how lucky the world is, because if women had periods, they would break down from the emotions and the pain and the food cravings, and the end of the world would be nigh. Obviously such a dramatic bodily function can only be dealt with properly by tough, manly men.