We currently use vBulletin as the software that powers Mustang Evolution. However, vBulletin has fallen drastically behind in some new useful features that are currently offered by Invision Power Services
I am considering converting this site to Invision Power Services
instead of upgrading to vBulletin 4.
I would be interested to hear some feedback on it when you get a chance.
We would keep the same look and feel as we currently have as far as colors go. This won't happen for awhile if we do choose to go this route. I really think it will be better for the forum than sticking with vBulletin. At the moment at least.
Here is a preview of their new profile commenting system: Invision Power Services -> IP.Board 3.1.0 Development News
You can also integrate your facebook account with IP.Board. It's built in so it will be 100% stable.