In my last post I referred to an article that compares various online mapping servers.
Now you can see the effect for your self. ocarto allows you to overlay 7 layers of maps from Google, Yahoo, MS Virtual Earth, and Terraserver.
44.300572,-78.339096 in ocarto, and zoom in all the way. It's the town of Peterborough, Ontario, Canada.
You can search for the nearby town of
Royal Oak, MI to see a lot of new development, roads that don't exist on many maps, existing on Google. (I'll send them a cookie)