Overall
This site shows a comparison of named features in OSM to a list generated by the Federal Statistical Office from the Eidg. Gebäude- und Wohnungsregister (GWR). The GWR contains information on all houses and apartments in Switzerland and is updated regularly. By definition OSM will typically contain more named features than the GWR list, however it is fair to say that the GWR will contain essentially all inhabited places that you would want to navigate to, georeference or similar.
Please visit the OSM wiki page for more information.
