
Pear vodka is a flavored vodka — a neutral base with pear added, so pear is the dominant note.
US law lets a flavored vodka be bottled at 30% where plain vodka must reach 40, so an American bottle can carry less alcohol per measure. In the EU both must reach 37.5% and there is no gap at all. In practice the major pear vodkas sit at 38 to 40 either way. Fresh fruit with plain vodka gives the note without the sugar many bottles carry.
Pear brandy / eau-de-vie (Poire Williams)
Pear vodka is a neutral vodka flavored with pear and stays a vodka; pear brandy or eau-de-vie is distilled from fermented pears and takes its character from the fruit itself. The eau-de-vie is drier and far more aromatic, so it leads a drink the vodka merely tints.
At 38 to 40% the spirit itself is stable; what is delicate is the pear. Keep it cold and closed. An opened bottle is best measured in months, and the fruit note is the first thing to go missing.