Updated via Kies (Phone is on Vodafone) yesterday. No real big differences, I think TouchWiz has hidden or removed a lot of the new stuff which is a shame. However, the update was easy and no data was deleted so kudos to Samsung for that at least.
Some annoying things that aren't working include not being able to silence the phone by turning it over and an annoying bug where the share menu in gallery is limited to only a few apps. Favourite things so far include data usage meter, new multi-tasking display and the swiping of individual notifications to clear them. Also a few annoying bugs have been fixed from gingerbread including the voice command popping up when pressing menu from some apps and no vibrating for notifications.
Looking forward to a stable CM9 to flash though, I want to give (pseudo) vanilla Android a whirl.