One note on what sch said...
There are two kinds of gatorade. The powdered stuff is sweetened mostly with sucrose, which can be absorbed fairly well. The pre-mix is sweetened with fructose, which has a different absorption mechanism which is limited in amount. If you exceed that amount, you will get the dreaded "GI upset".
Gatorade may also be too sweet - other drinks use carbs that aren't as sweet so it's easier to drink.
Finally, Gatorade has a new "sport" formula that I don't know much about.