The ingredients include sparkling water, white grape juice concentrate, cane juice concentrate, and lemon juice concentrate, along with a blend of herbs including things like ginseng, Echinacea, and Ginkgo biloba leaf. The caffeine comes from 125 mg of guarana. That description sounds more like a recipe for herbal tea than a carbonated energy drink, but Guru tastes surprisingly like a fruity berry soda.
As for the energy rush, it's decent enough if you're going to ride a bicycle for miles, play some basketball, or do some other healthy physical activity, but with only 22g of sugar, it's not a mighty mental stimulant at all. That's okay. The purpose of an energy drink is to provide energy, rather than just alertness, and Guru's a good choice for people who want to try an energy drink that's not loaded with carbs.