While marketing behind a lot of the popular "energy drinks" suggest stimulants and "energy" or such, my understanding is that there are a number of things you want for proper re-hydration beyond water and salt which is is supposedly the drive behind the formulation behind drinks like Vitalyte.

My guess is that caffeine and lots of corn syrup which dominate many of these "energy" drinks is counterproductive to both proper hydration as well as long term energy management.

I get the impression that Gatoraide started with proper hydration as its goal, but with less science and over time, dilution of intent with the increase in things like corn syrup.

While I haven't done any real research on the matter, I categorize these into three groups in my mind:

1) Serious minded hydration drinks
2) Mainstream hydration drinks
3) Bogus "energy" drinks

I do think after watching some lectures on the topic that plain water isn't the answer in severe hydration situations, and if you accept that, it all comes down to the relative effectiveness of various solutions and the cost effectiveness of same.

Personally, I like lemonaid (w/sugar, not corn syrup) after working outside in the sun. But I'll put some Vitalyte in the pack when hiking.

YMMV.

-john