I've tried all of them, and there is a definite improvement as the price goes up, but not proportionately with the price -- and more importantly, less than you get with the corresponding cognac grades. I'd rate it at about a 10% improvement at each level ... so the best is less than twice as good. By contrast 5x increase in price in brandies will yield much more increase in quality. I find mixing regular grand marnier with hennessy xo to be higher quality than the Cent Cinquantenaire for example (and using Paradis would be much better). I suspect they don't use the best cognacs in these blends, despite the labeling, based on what I've tasted.