While vB has a nice feel to it, for some reason I just hate it. I guess it's the free-open-source part of me coming out. I have been a *nix nerd all my life and still like phpBB. SMF was one that I thought was a real contender with vB, but i haven't had much time to play on the admin side of things with it, other than a few local installs.
vB is very smooth in the heat of action, I used to mod and smod on forums with 300,000+ members and vB rarely skipped a beat. Glad you guys found something that will make the mods and admins much more comfortable.
YaBB is another great open source board, but the limitations it has with regards to a database make it very difficult for a forum of this size.
Hope the mods and admins enjoy the comfy toys that come with vB. :)