One thing that I noticed when setting up my iPhone 5 from an iCloud backup was that all of the apps were downloading and installing simultaneously. Before, if I recall correctly, the apps would have to be installed one by one but with the iPhone 5, all of the apps were being installed all at once and at a really fast rate.
Not really something I'll be doing on a day to day basis but impressive nonetheless.
I don't think that's new with the iPhone 5 or iOS 6. I'm pretty sure on my iPhone 4S with iOS 5 it was the same. I believe that feature was introduced a while back.