To be honest I'm not too excited about this. I don't want to relearn using a computer just to use a new operating system, and I definitely don't want to learn something that's completely different from the other OS I use on a daily basis.
On the plus side, this almost obligates them to include some decent GPUs in the MacBooks.
Well, people have migrated from CLI to GUI quite easily. What makes you think that any kind of change in the UI would be difficult to learn?