From what I've read (and it seems entirely plausible), Google wouldn't allow Apple to use the data for certain things - though Apple built the app itself - such as turn-by-turn as to give the Android offering a competitive advantage.
As has been pointed out before, Google was not allowed, by its data suppliers, to let anyone else make turn by turn apps. Apple had to negotiate their own contract to be able to do that.
This is because data providers make most of their money selling map data for personal and built-in auto GPS units. It is not in their interest to let every yahoo on the planet make a TBT app using their data, for free.
Also I don't get why Apple maps data is so messed up when they in fact are using TomTom maps. The data on TomTom appears correct while it is wrong in Apple maps.
Sidenote: TomTom bought TeleAtlas, which is generally ranked below Navteq in accuracy and completeness.
However, TomTom has already said that Apple's woes are not the fault of TomTom's map data.
Apparently it's all in how they interpret the data and map it to other information.
3) I don’t believe Microsoft or Mapquest offer turn-by-turn directions, 3D views, vector or OpenGL maps, etc… that’s one of the reasons why the Lumia series uses Nokia’s mapping service.
Microsoft Bing Maps have a 3D "birds eye" view at least in the USA: they used low flying airplanes to collect the images instead of satellites.
As for Nokia, they bought Navteq, one of the best mapping sources in the world. (Google used to use them for their US maps, before that. Garmin still uses Navteq.)
Actually it is snappier - maybe not as accurate, but the vector-rendering is much smoother than Google Maps!
Smoother than the ancient iOS version, yes. Google Maps on Android has had vector rendering for quite some time now.
Android users assure me that Google Maps on their phones does really do automatic turn-by-turn. Am I overseeing something or is Apple Maps lagging in this respect?
Android has had a far superior set of Google apps for a while, including transit maps, building interiors, and true turn-by-turn voice aided Navigation. The iPhone never got all those features.