Energy drinks: pro or con?

Almost every time I am drinking an energy drink, or talk about drinking an energy drink, someone says, "Oh, they're so bad for you." Well, everything is bad for you, isn't it? (she groused with no attempt to hide her irritability) I mean, life is going to kill us all at some point. In all seriousness, though, I haven't researched them except in terms of deciding which ones I like the taste of--and I only drink sugar-free, of course. I also have never drunk more than one in a day, nor would I--especially not prior to a workout.

I'm not particularly fond of Red Bull, though it is okay as a drink mixer and most places seem to have some sugar-free behind the bar. NOS has been my favorite thus far in terms of taste (despite the fact that it is the official energy drink of NASCAR, which did give me pause)--it's more citrus-y than the others--but I have had a hard time finding it in sugar-free, or at all. I heard that Wal-Mart recently pulled NOS from store shelves for causing heart palpitations in someone somewhere, but I would also be willing to bet that the person/those people pounded several of them beforehand, and that it may or may not have been the same person who sued McDonald's because they spilled some coffee on themselves and found out (shock! horror! disbelief!) that it was hot.

My happy medium for energy drinks seems to be Rockstar, which can be acquired by the case at Costco for the cheapest price I've seen, and can be found in sugar-free just about everywhere.

Yes, it has a lot of caffeine--80 mg in a 16-oz. can--but want/need for caffeine is usually why one drinks one of these, isn't it? There are 0 carbs and 20 calories in said can, which also contains 200% of the RDA for Vitamin B2, 100% of the RDA for Vitamins B3, B5, B6 and B12, as well as taurine, ginseng, guarana, ginkgo, L-carnitine, and a few other things of that ilk that are said to be beneficial to one's overall health.

If dairy and/or coffee are hard on one's stomach, I guess I don't see the harm in energy drinks. They are "lightly carbonated" as opposed to the full carbonation of soda, which is preferable for post-WLS folk. There is no aspartame (at least not in the sugar-free Rockstar can I have next to me as I type this). I'm going to have to talk to my nutritionist next time around and see what the big deal is.