After seeing how vodka is made, how can any of it be considered "high-end"? It's all the same unless it's been distilled through a truck radiator.
Same as beer, the ingredients/quality of water/type of components used in brewing equipment.
I can definitly taste the difference between Pravda (polish), Gzhelka (Russian), and Crystal (Russian) and American brands like Popov or Crystal Palace.
I can tell the difference between Shipyard IPA and a fresh from the brewery IPA also, even though Shipyard does a darn good job of acheiving the same taste.
I am a very occasional drinker, and even then never more then my limit is generally three, but I have noticed a huge difference. I don't know if it is component of the cheap stuff, but I do know there is a difference in quality of vodkas.