Amp's energy drinks are not my favorite, though i do not hate them either. The difference between amp and rockstar and monster (two of my favorites) is that amp does not seem as refreshing as the other two. It is a little too much of pure energy to me. I feel when i drink monster during a workout it is like drinking some ice water, but amp is like drinking burning hot coffee or something, it rages you up rather than refreshes. For physical energy, it is pretty good, but for mental energy, there is too much of a burn and minor headache that comes along. plus, it does not taste near as good as other drinks to me.