I tend to use the "decaf" version (note that even their decaf version has -some- caffeine) but sometimes I need the extra kick of their normal version.
They also have a double-strength version. I've only used that kind once. It kept me VERY wide awake for about 8 hours but it was a bit too much caffeine in one gulp for my liking... If I want to stay up that long in the future, I'll probably use two of the standard strength bottles and take them about 4hrs apart.
All of the 5HE shots advertise that they keep you from "crashing" when they wear out. I'd say it's true. When I use them, at the end of their effectiveness, I feel like I'm reaching the end of a long work day -vs- feeling like I suddenly need to sleep for 16hrs+ like I've felt with some standard "energy" drinks.
Most places that carry them around here charge $3 each. They also come in 2 and 6 packs for about $5 and $13 respectively. I've also found occasional sales on the web where you can get them for about $1 a bottle, but you usually will have to buy 24 (or more) at a time to get that kind of rate.
Anyone else tried them? What's your experience?