I’ve tried a couple of flavors (orange and lemon-lime) and they’re not bad.
As everyone else has said, they’re much easier to carry and parcel out as needed.
According to Jelly Belly when I talked to them about it, they said that they noticed that athletes were already using jelly beans for quick energy – it’s much neater than Gu or other sport gels. So they were just trying to fill in the missing ingredients.
They taste a little salty to me, but then again, so does Gatorade.