For my area, Apple has several zoom levels of detail less than the others. It shows the small streets but not their names. Google and OSM zoom to the same level, but OSM shows more details like walking paths and power-line rights of way. So I'd use OSM if walking or biking, Google if driving, Apple never.
Given Apple's usual attention to detail, I was surprised to find missing Unicode characters in the font used to render city names (the missing character here is "ə"): http://i.imgur.com/pFZ5s.png
This is a beautiful interface to let everyone decide for themselves. They appear to be three slightly different datasets, my neighborhood looks minimally but non-trivially different in all of them, no two are the same.
