If you get the height just right (have it just clear your head), then putting up or taking down the bike is a snap. One key is to not do both wheels at once, because then you're doing a balancing act with the bike high above you.
That is, when taking it down, put your hand on the saddle, unhook the rear wheel, rotate the bike down so it's hanging from the front wheel. Then put your hand on the seat tube, and unhook the front, lower it down, and rotate it to wheels down.
My Book: Drive, Ride, Repeat: The Mostly-True Account of a Cross-Country Car and Bicycle Adventure
I over-extended my left arm trying to hang a bike a couple of years ago I damaged my shoulder which over the course of several months started to freeze and eventually ended up with a frozen shoulder (adhesive capsilitis). It took me over a year and a half to regain most range of motion in my left shoulder.