One caveat for you is old styles you used to use will need to be updated.
This can be done from the member area where all the old stock styles per version have been updated for the current version that you can download.
But other old custom styles will need to be revisited in the style editor due to the newer UBB version is using css tags that were not in the older versions.
It should not be that difficult for someone like you but it does exist.
As a long time user myself of UBB I can say it has become a great product again. with current hosting standards.
Upgrades and install are almost %100 bug free now as well as Gizmo has developed a pre UBB install test script.
And the Stop Forum Spam add-on is now stock. As well has been upgraded to detect not just new registrations but existing members also.
Kudos to Isaac and Gizmo.
