The OTA worked on my hubbie's stock Thunderbolt. Mine is rooted and when it rebooted, it was soft bricked with the little blue android doo-hickey and yellow triangle. I yanked the battery, rebooted into Revolutionary boot menu, cleared cache, rebooted, had the same problem. I yanked the battery again, rebooted but this time I re-installed the PG05IMG.zip file that I left in the root level of the SD card and after re-installing from zip, everything became operational with no problems. I immediately ran a backup by rebooting again into the boot menu and performing a full backup which took a while, just in case... No problems since.
And to date, I still haven't found the app to freeze that would prevent the OTA push from automatically attempting to install. How annoying!
By the way, the Thunderbolt hardware doesn't have sufficient CPU power to run full ICS with the spinning menus. You'll have to upgrade to a phone with more processor power to get ICS with all its known features. If I can locate the link where I read a detailed explanation that this is why we're not seeing full ICS for the Thunderbolt, I'll come back here and post an update. I was bummed when I realized that was the case.