Jason,
We just transitioned LinksysInfo.org from phpBB to vBulletin and are very happy with the results. Congrats on your move as well! We decided for almost the exact same reasons you have stated. I'm sure you've begun to discover some of its quirks; we are still discovering more, but phpBB obviously had its own! We are still trying to settle on a CMS that will deliver the site as we'd really like to present it. Have you got any thoughts short of your custom solution?
James Depew
www.linksysinfo.org