I can generally taste the difference. The bad has a certain taste to me that's just absent in good vodka. Favorite cheap stuff is still Russian Standard and if I could get Karlsson's here, that would be my premium go-to. My 2 cents: I have tried the brita filter trick with crappy product and the change is not insignificant. 5 runs through a normal, disposable filter got rid of most of the harsh, nasty flavor. The only cost was an hour of my time and a filter that now makes water taste like vodka.