If you like map comparison websites, you will love this one !
GeoFabrik's Map Compare allows you to view several OpenStreetMap layers side by side with different Google Maps map types. The two maps are synchronised so zooming or panning one map will zoom or pan the comparison map. Geofabrik is the work of two active German OpenStreetMap contributors, and the Map Compare tool was developed to allow Geofabrik to compare OpenStreetMap map offerings to Google Maps maps and aerial imagery.
From GoogleMapsMania
