Right, doesn't seem like anybodys' a fan of the lore-perspective, so lets take into account game mechanics!
Pros and cons (that matter in a fight):
Vampire:
Increased attributes and skills. (I know skills can go above 100, not sure about attributes).
Werewolf:
Fixed stats (at 100 or below).
Double health
Claws as weapon
Weakness to silver weapon.
I think the werewolf loses out big time by not being able to use magic, armor and weapons. Also that the vampire has the potential to jump farher and run faster than the werewolf (right?). Even so, it'd be close, seeing as the claws are great, and that they have lots more health. I don't think comparing the vampires in the game against the werewolfs (who are in the expansion and some of the toughest monsters in the game) is really fair.
To sum up my views on how I think it'd go, the vampire is more sneaky and can run around putting arrows and magic and attack the werewolf. The werewolf however, can survive quite a lot and if/WHEN it catches the vampire, he/she's a goner.
