Looks like a great update: shared Photo Stream support, send audio to AirPlay-enabled speakers, iTunes account switching, new Screen Savers, reorder icons on main menu, etc.
For some reason I haven’t been able to get shared Photo Streams working. Whenever I try to turn it on it tells me that iCloud’s terms of service have changed and that I should go to Apple’s iCloud support page. But, there isn’t any information about how to troubleshoot the issue. Hopefully they support page will offer some suggestions soon.