Just for starters, we've gotten some consistent complaints from others about the design of the forum being too old. (I personally didn't see an issue with it but whatever.) Another thing is that SMF has a verrryyy slow release schedule. XF was kind of leaving it in the dust. Yet another thing is that XF will give us a more power in terms of how we wanna do things and what we wanna do. For example, XF has a resource manager that will allow us to upload and share... Well, whatever we want. Then there's a nice little media gallery. And finally, if something goes wrong with the software, we have guaranteed high-level support. Oh, and also, there's the greatly expanded search. And deep style customization tools. Probably missed a lot more, but I'll leave it at that.
We have lost a couple things in the transition but I'll detail in a later post.