Powerade is nowhere near as supplemental to the body as Gatorade is. Powerade does not replace sodium lost in sweat as well as Gatorade. Not to mention, all flavors of Powerade except the blue one taste like rat piss.
If it were Powerade vs. Gatorade, I'd choose Gatorade every time.
However, I'd go with water before either of those two any day.