I once took a paintball to the bare side of my neck from 5 or 6 feet away. It split me open and the lump swelled to the size of a baseball. I still have a scar from the wound it left. I haven't played since either. I used to be an avid player though, I played rec-ball guerrilla style in full camo, some guys in ghillie suits. We made shields and shoulder mounted paintball cannons that could fire up to 200 rounds at once, accurate to about 50 yards. The minimum safe distance was about 30 yards so they weren't used much.
My favorite gun that I had was a Spyder Esprit with an electronic 6 way dual finger trigger assembly, a flatline barrel that was home made by my Engineer uncle, and a standard hopper.