I've been playing with it for about an hour - and I think one of the interesting tricks that the Google Maps plays is that, in addition to making aggressive use of cacheing (which the IOS 6 map application does as well) - The Google Maps displays low-resolution version of the map you are moving into, before display the high res. The IOS 6 Maps app tends to display a blank background, so you may be more aware that the entire map hasn't been displayed.

It will be interesting to see if there is any server impact, as millions of people start using this Map Application tomorrow. (In both directions - it may be the case that the Apple Map servers will see a drop in use, and increase in performance)

It seems that he is talking about how fast new map data/tiles download and display when you are scrolling/zooming the map.