One advantage werewolves will probably have is, leveling up the perk tree.
The Vampire Lord must hold back his destruction and be sure his drain life or power bite kills enemies to perk up. His followers or his summoned gargoyle could steel feedings by slaying enemies. I imagine a lot of frustration from 'accidental kills' with the wrong ability or and ally thus denying you the vampire xp. Plus trying to perk up a vampire lord if you're already high level could have its own problems.
While the Werewolf and his allies can finish off foes with impunity as he feeds on corpses.
This is an aside, but does anyone know how strong the Totem of Fear makes your howl? And how strong it is naturally?
Good question, not even the usep has the answer yet.