I pretty much live on this stuff. Don't know how you can beat the no sugar, 8 kcals, loads of B vits, herbs and caffeine for kick - and six flavors!
Rootbeer's pretty sweet, too....
Mixing is a hell of a lot more fun when you have the different flavors to choose from, also. Parrot Bay and the grape-cranberry is my fav, followed by Maker's Mark and cherry.
I'll pick up any of the other brands out there from time to time (mainly because I didn't plan ahead) and they all taste pretty much like the same lemony-limey-citrusy crapola and don't do much in the "energizing" arena.