The forum is the forum because of the people, not what runs it in the background. I am not familiar with VBulletin so I am not sure all of the additional features behind the scenes that are happening. It could make moderating a lot easier, I don't know. It may be worth the benefit. Whatever it is, we should embrace change if needed and not be old farts and reject any change out there. Make sure that VBulletin is worth it, if it is, go for it, if not, then don't.