I think I am going to go against my instincts and upgrade to the latest version of vBulletin. You will probably notice a few errors during the process. Hopefully this isn't going to be as painful as I think it will be.
Yea... the PM system got a good bit of attention. The rest of the features is mainly vBulletin fixing all the crap they put into 3.7. There are some things that will make my life easier in the backend too.