Dripping Springs is preferred by many in these parts..

It's likely "Kirkland" Vodka comes from whoever is the low bidder at any given time, so I wouldn't count on consistency.

The only way to test food or beverage is "double blind" so the server and consumer are both unaware of the source. The results are often surprising. We did this many years ago with beers and the rankings were almost exactly reversed between the blind and brand-identified beers.