This might be the 3D map that Nokia will use in their phone if you want to compare: http://maps3d.svc.nokia.com/webgl/index.html
I wonder if the iPhone 5 will have a bigger screen. The iPhone 4 screen seems very tiny compared to my Galaxy Nexus. What is the use of fancy 3d if the screen is tiny?
Actually we do. Apple supports 26 cities. Google supports 13.
Where did you get those numbers? As far as I can tell, more that one hundred cities have textured buildings in Google Earth (they were created by building maker https://www.google.com/intl/en_uk/earth/learn/3dbuildings.ht...) as well as in mobile maps (http://www.google.co.uk/mobile/maps/3d/ my city has 3d outlines and it's not even in the map). Apple maps too should have at least 40 cities in 3D.
Actually Google and Apple have pretty similar systems for 3d maps. Apple are in beta with their new version for ios6, which will have slightly better resolution than (the current, been there for a while) Google Earth, but not hugely so. See for comparison http://www.iphoneincanada.ca/iphone-news/3d-maps-comparison-...
Nokia are producing similar 3d maps, although again slightly lower resolution than Google.
I think more importantly than resolution will be coverage. 3d maps of the centre of major cities are one thing, but the whole world is a very different challenge, and one we have no clear idea of a winner on.