I am Jo a fan of regular energy drinks, the only reason I like that rockstar one iis because of the caffeine, so in that case the flavor is tolerable. Nowadays I just stick with stuff like 5-hour and spike doubleshot, less liquid but more adrenaline and the price is somewhat the same. Depending on the time of the semester I sometimes play around with the amounts and go for something more over extended amount of hours.
I think the most I topped at was 1.3 grams of caffeine, no-doz, and on top of that unknown amount of b12, but that was over 10 hours in the library, the gradual intake helped but still was very rough initially for the first hour or so, and from there it was smooth sailing into the morning hours.
Haha, college will kill me by the time I graduate. :-|