Scott, do you have plans to upgrade the site to the 4.x branch of Vb now that it's been released or are you going to continue with the 3.x?
We own vBulletin 4 and are running a test site using it. However I don't like it yet as it does not seem like an upgrade to me.
In addition a number of our modes (such as the selective forum filter which lets you hide forums you dont want to see) and another mod which imports emails as a forum message are not available on vBulletin 4.
We need both of those mods to be working on vBulletin 4 in order to move to it. All of the other mods which we run have been ported over, so we are good there.
I also must be honest I don't like the look of the new vBulletin. Text is too small and finding things is hard, again the new software seems like a downgrade to me.
So we will be here for awhile as long as we dont start having issues with our current software.