Works perfectly.
AT&T Samsung Focus in Hunstville, AL.
Cleared my music from the phone - so I had 4.3 GB of space available on the phone. Then used Chevronwp7 to unlock, used another tool to sideload Samsung Registry Editor xap, then unbranded using Samsung Registry Editor. Zune immediately found pre-NoDo update. Update process was flawless. Getting the NoDo update to show up took a couple tries, but once found it also proceded flawlessly.
Samsung Registry editor no longer functions afterwards and a message appears saying it has been revoked by MS, please uninstall.
I have been using the phone heavily all day and everything is normal. Still have access to AT&T apps, all phone features work normally. Significant speed improvements in loading many games, and resuming apps from lock screen (those that don't "run under lock"). Marketplace crash appears to be resolved. Marketplace filters based on the category you're in. C&P isn't the PITA to use that iPhone's is, but only certain read-only text is selectable. You can copy from web pages in IE, but you can't copy something like an existing facebook comment.
So, not necessarily something you have to rush out and get, but also not a major hassle to get early either.