Well it depends on which research, or people you talk to.
Yes it's unhealthy, but some people make out it's worse than cocaine and your magically going to drop dead from it lol.
Fuck, I've even heard some tea drinkers make out the same crap about coffee.
A lot of the news articles of people dying from energy drinks, usually leave out important factors, such as the person did drugs before hand, or had heart problems in the first place.
I think the same goes with anything though, some people even make out violent video games cause violence, and if that was the case you'll see a massive number of heart attacks between coffee drinkers, and more serial killers who played GTA.
I may drink a lot of caffeine, but I have a high caffeine tolerance, if you gave a 8 year old the amount of caffeine i had they would probs OD lol.