The weight distribution is nice, not only for your back, but also for whatever is in your bag. When full the contents seem to be under less pressure in a messenger bag than in my backpack. The only evidence I have of this is that when I made a grocery run with my backpack, the gallon of milk ended up dripping out the bottom. I've never had a gallon of milk bust in my messenger bag. Milk is really gross to wash out of your saddle and drivetrain by the way.