And I hear ya on the passwords. vB is tough on that. Even admins can't see the passwords.
At least for me, I'd really be looking to just get posts/threads and the forums. I have a UBB I'd update to the newest version, then I'd simply bring over/merge all the posts from a vB board into the UBB. No users, though the original posters names would still be nice to have at least rather than "Guest".