Should I use Hammer Gel or HEED?

Either, it's your preference!

Both products are ideal for use during exercise of any intensity lasting up to 2-3 hours.

Hammer Gel is a concentrated complex carbohydrate gel with the consistency of syrup. It is the best choice for athletes who prefer drinking plain water for hydration.HEED is a powdered sports drink mix. It is the best choice for athletes who DO NOT like drinking plain water while exercising.
Offered in 12 flavors: Apple-Cinnamon, Banana, Chocolate, Espresso, Montana Huckleberry, Orange, Raspberry, Tropical, Vanilla, Nocciola (Hazelnut), Peanut Butter, and Peanut Butter-Chocolate.HEED comes in five flavors: Cherry Bomb, Lemon-Lime, Mandarin Orange, Melon, and Strawberry.
Caffeine Quotient: Espresso contains 50mg and Tropical contain 25mg of caffeine per serving.Caffeine Quotient: Cherry Bomb contains 25mg of caffeine per serving.

Either product can be used as a partial source of calories during ultra distance events to provide variety and flavor to your primary fuel sources, Perpetuem and/or Sustained Energy.