It's pretty sad how easily consumers can be fooled by cheap tricks like a frosted bottle and the words "made in France". They don't even need the help of alcohol to make poor decisions :p
Taste of the vodka is irrelevant. You drink it to get drunk, not to enjoy the taste. So, for example, vodka on the rocks makes as much sense as deep fried caviar - it's a pointless waste of a product. Secondly, and most importantly, you are looking at whether you get a hangover in the morning or not. That's it. So the criteria for a good vodka is (a) doesn't make you cringe when drunk and (b) no hangover.
Stick with Wyborowa or Stolichnaya. If not, get a really cheap one and put it through Brita filter a couple of times. This removes all impurities (specifically - the fusel oils, which is what actually hurts the head in the morning), and it will be as good as high-grade commercial product.
(edit) By the way, another way to filter cheap vodka is to mix it with cranberries (ideally the wild ones), mush them and let sit for 24 hours. Filter and enjoy. Cranberries absorb the oils and infuse vodka, so not only this reduces the hangover effects, it also makes the vodka significantly more pleasant to drink.
Any russians in the audience care to clear things up?