It really depends on which "brand" of werewolf or vampire you are talking about.
With fiction it is generally very hard to depict one or the other stronger because there are so many variations.
Take for example, Vampire Diaries - A werewolf bite kills a vampire, or take older stories where vampires could control wolves. There is no right or wrong answer just opinions based on what type of vampire/werewolf comes to mind first.
idk... really depends what vampires and werewolves you're using. if elder scrolls, vampires without question. all sorts of horrible magic, and a vampire lord that only increases their magical potential.