Have a look at jdub's comment on the item about Ars Technical review of GNOME 3. He summarizes pretty well what will happen (or not happen) in Ubuntu with regards to GNOME 3:
http://news.ycombinator.com/item?id=2419435
I'm unclear on how the changes relating to the desktop will actually change the experience.
Congratulations to the Gnome team though! It does look great.