Apple's old map was OpenStreetMap plus other sources but its new ones are proprietary. But its new ones are only available in the US, UK, Canada and Ireland.
I believe the old map was mostly TomTom (TeleAtlas) with a little bit of other sources sprinkled in.
Yes, more TomTom that openstreetmap, that was clearly show by the dataquality. Much less walk and vike information. If you don't drive a car all my sampling say OSM is way better.