I upgraded one of my discussion forums today – ZooBeat :: The News on Zoos.
I’m now running vBulletin v3.5.3, and the upgrade process was very smooth. There are quite a few new features in v3.5.x – but not many of them are visible to end users. The vast majority of the changes are to the backend and administration interfaces.
There is lots of Ajax to make administration and moderation easier, new inline moderation capabilities, data APIs (for integration with other systems), template history and comparison (diff) features, database thread and forum read marking (users will like this), and much more. One of the biggest changes though, is the new plugin and hooks system, which makes extending the product so much easier, since you no longer need to hack source code to integrate other products and extensions.
vBulletin costs US$160 for an owned license, and $85 for a 1 year leased license. There are bulk discounts available if you’re buying multiple licenses.