I don't think much of them but a little reading might help you make up your mind. Lot's of caffeine.
Caffeine in G Fuel Energy Drink MixG Fuel Energy - Possessedbycaffeine.com
Are energy powders/formulas such as G-Fuel healthy?
You are speaking about caffeine right? What is the difference. Also seen those caffeine tablets in dollar general if you don't like what ever is added to those drinks.