Upgraded (OTA) this morning
Got a whole-file signature failure from CWM but it seemed to upgrade anyway.
Initially, most things looked fine, but Camera FV-5 (an excellent app) still had the completely broken preview - looks like bits of the rest of the screen replicated all over the place.
So I thought I'd try a reboot. When I rebooted, I had the wallpaper and the notification bar, but nothing worked - no app icons, couldn't pull down the bar, swiping left and right caused strange corruption in the notification bar, menu button didn't work.
I got a bit concerned I'd borked it, but battery pull got things working again
Camera FV-5 still has broken display. I think this is what I got with R2 after I set the HW overlay option - if I didn't do this, the preview was OK. Standard camera app sees fine, and the pictures taken with FV-5 are find so it's some sort of rendering issue.
Also, would any of the changes have affected the 2G/3G reboots? I don't think so from the change log, and I got one this morning (I can pretty reliably reproduce this on the drive home from town - oddly, driving to town (same route) doesn't do it).