The thing is that they taste good.
But there is no justification for their price tag( coca cola and pepsi sodas actually fall in the same bucket,quite good but why would you buy them for that price,especialy since it costs them next to nothing to make ).
As far as I can tell, the difference between the brand colas and the non-brand ones, is that the brand ones don't destroy my guts. 2 cups of the cheaper colas and I'm shitting liquid for a week.