Apple maps requires data just like the Google map app.
I unfortunately have a Verizon iPhone so I can't do voice and data. When I'm using Apple maps while on the phone it works unless I miss a turn then it reroutes constantly since there is no data. Very annoying.
No. Apple
Maps uses vectoring so it automatically saves some level of detail without a data connection.
Exclusively use Apple Maps for turn by turn, in the US. Interface is much better than google maps. Period.
POI and street view in google is good though. 3D driving in a city with Apple maps is great!