I used to work a job where energy drinks were ubiquitous (as well as coke and meth to a lesser extent), and of the dozens I've tried, I found 5-Hour Energy to be the best by far. There's no sugar, and limited caffeine, and usually very little crash, just a gradual comedown.
What separates it from the rest in my opinion is the phenylalanine and tyrosine, which your body converts (along with the other co-factors contained in the shot) into dopamine, norepinephrine (noradrenaline), and epinephrine. There is also glucuronolactone in the energy blend, which Red Bull has but most other drinks don't. There is also an enourmous amount of B-12 in the drink (8333% of the RDA), but I believe it is used as a methyl donor along with its more traditionally accepted functions, hence the large dose.
Basically in my opinion, the caffeine in the drink is for an immediate effect, and by the time the caffeine and sugar in a regular red bull type drink is wearing off, the main effects of the drink are kicking in.
Sorry if this sounds like an advertisement, but I've researched quite a bit about nutritional supplements and was waiting for someone to finally clue in and include tyrosine and phenylalanine in an energy drink.
The ingredient list for 5 Hour Energy is
here. The smartest formulation yet in my opinion.
If I were to start my own energy drink company, I would basically rip of 5 Hour Energy, include 3-5mg of desoxypipradol, and call it 24 Hour Energy