I am a bartender and I'm constantly engaged in this debate. Strictly speaking, vodka is a, "flavorless, tasteless alcohol". Within that definition, vodka has differences that many so-called experts are able to taste. As far as I'm concerned, as soon as a mixer is added to a vodka, all bets are off, and I challenge anyone to a blind tasting where they will be able to detect which brand of vodka is in the drink. I have had countless amounts of people come up to me in the bar and say that they can tell which vodka is their favorite vodka. I have done blind tastings of straight vodka, at room temperature and chilled, and it is remarkable that everyone to date has failed to correctly identify their favorite vodka. For the record, it seems that when experts judge vodkas, that Chopin (potato vodka) consistently ranks on top of the competition. With that said, my advice as a bartender; if you are drinking straight vodka, choose the label you prefer and that makes you happy. If you are having a blended drink, just use rail vodka. Save the rest of your money for headphones... or for single-malt scotch. : )