Slashgeo points to an article at Off The Map on the worldwide comparison of OpenStreetMap vs TeleAtlas street coverage.
"(...) OSM is slightly ahead of Google/TeleAtlas worldwide and in in Africa and Asia. In Europe, OSM is well ahead. Google is slightly ahead in Oceania, and well ahead in North and especially South America."
It is explained as:
The size of the circles are proportional to the values for both, so small circles equal poor coverage and large circles equal good coverage. The overlap of the circles shows who appears to be doing better (orangey/brown showing means that osm is doing better, blue google). OSM is the top layer so a tie will have OSM looking better, but you can click the layers on and off to see both views of the coverage.
After playing around with this a while, a funny artefact comes up:
Monaco isn't Munich, folks.
Italians sometimes take "Monaco di Baviera" for Munich. "Monaco" officially is the "Principality of Monaco", a small sovereign city-state located at the mediterrean between Italy and France - best known for their wealthy inhabitants and tax refugees.
