i don't really drink energy drinks but in the zoo mags over here they do a section each week called 'pub ammo' basically just loads of facts and useless knowledge. in one magazine it mentioned rockstar energy drinks several times, apparently they contain loads of chemicals that aided in everything from speeding up the metabolism to helping lower risk of diseases (cant remember which one it said). would never pick an energy drink for having so many benefits.
obviously overall they're not good for you but some of the chemicals or whatever in these drinks did sound beneficial
i'll try and dig up exactly what benefits these rockstar have in them, unless someone else knows off top of their head.