The Perfect PushUp follow's the natural twist of the hand/wrist, forearms/elbows and shoulder joints. Much less tension on all of these. Like doing chins with a set of gymnastic rings or even with rotating cable handles, which can also follow the natural hand twist. Like when throwing any kind of straight punch, the fist is twisting at the start and finish of the strike. It is all about torque power and the natural way the strike is used.
Pushup's are somewhat limited for max development but could suit people who want to achieve a certain amount of muscle, just for the sake of staying in some form of shape. Would be interesting to see if that Perfect PushUp device could be used for handstand pushup's. That is a great upper body builder. Could even put your feet on a bench, chair, table, etc so more of an incline effect is gotten. Good Luck.
Side Bar: Like to be the guy who invented it and put it on the market. Christmas time and all that, it should sell very well.