I grew up hand nailing , it was allot of work. Allot of people think this is the best but I have seen allot of nail pops with hand nails. Gun nails are very hard to get out because of the wire that goes in with them. You ever tried to tear off a gun nailed roof it pretty hard. Gun nailing just gets a bad name because so called roofers shoot through the shingles when it gets hot or cold, to lazy to adjust the air pressure. Or they dont want to ever have to pull there hammer out, so the keep the pressure very high. It was cool to see some of those guys rock and roll hand nailing. The nails would go in so fast they would make your eyes water trying to watch them.