ReiseRadKarte's cycle map of the Netherlands based on OSM data
This map of the Netherlands is based on data from the OpenStreetMap Project. The focus of this map is to make it as convenient for bikers as possible. It gives additional information that are crucial for bikers (e.g. cobbled pavement, closes bike store, etc.) and the routing also focuses on bike friendly roads. The map can be downloaded directly as a gmapsupp.img so you can copy it directly onto your Garmin GPS device.
OpenStreetMap works that way, that everybody can upload their GPS tracks from which maps from all over the world are being created. This means that the quality of the map depends on the tracks uploaded by the users (you're welcome to contribute to the project by uploading your tracks as well) and therefore the quality differs greatly from country to country, region to region and city to city. As there are continuously new tracks being contributed the maps are getting better and better every day, so if a map of a region is not as detailed as you had expected either join the community and help by contributing and/or come back in a few weeks or months and you will most likely find a better map with more data and information than there was before.