Water should always be your first choice for re-hydrating after a workout, unless you're working out for more than an hour or exercising in particularly harsh conditions. The primary ingredient in both Gatorade and Powerade is water,
They are both made up of the same three things: water, carbohydrates and electrolytes. However, there are differences in the electrolyte and carbohydrate contents and ingredients of these two products.
Drink some natural fruit juice. It has no additives, dyes, processed sugars, etc. the natrual fruit juice has MORE of everything in it so your getting double the energy minus the crap.
Powerade and Gatorade really aren't good for you. You are much better off going for water before even reaching for the Gatorade. Sports drinks contain many substances, liquids, and chemicals that are so processed and very bad for you. They replace the electrolytes but not with wholesome ingredients you can build off of. It is like you mixed syrup in water- with the increased amount of sugar you are also consuming an unneeded amount of calories. So in short opt for water- it is nature's best gift to us... besides maybe pineapple.