water is better while you are exercising. if you consume an energy drink and then exercise, it may help, but during exercise, water is better...bear in mind also that energy drinks dehydrate you, so be sure to drink extra water.
energy drinks before a workout are good once in a while. you dont want to get into the habit so that you need one to workout...at that point it isnt enhancing performance, and you are just wasting a lot of money.