The Apple devices with GPS have a SIM card slot. This because they use AGPS for position initialisation, whereas many Android devices have regular GPS with processors that cope with initialisation without the use of cell-phone signals. I use an iPad at work which doesn't have a SIM card installed, as the company don't provide one. It takes forever to get a GPS lock, if it ever does. For private flying (running Sky Demon), sailing and hiking I use a Samsung Galaxy tab (no SIM) with both GPS and GLONASS. The Android device is far superior in every way, particularly at sea where you need a bright screen.