They are all scams, in that it's nothing but caffeine. The other ingredients aren't even in there, not really, they are pixie dusted so you can have it on the label.
Like I've said, caffeine is such a bad stimulant. At least you US guys can get ephedrine, a little ephedrine and a reasonable amount of caffeine, say 100mg, like a cup of coffee and it blows anything else out of the water. Don't you mofos want a smoooth stimulus with added mood lifting properties?
No I don't think they are particularly dangerous. We are old men but a couple of cashiers lectured us on energy drinks the other day, "do you know how many people have their hearts explode from this stuff!?"