I,m no expert but here is my understanding of using nav apps on your iphone/ipad.
I have an old ipad i beleive it is a version 2 with no gps chip, so i have bought a garmin glo gps receiver (which is about the size of a half packet of fags) the 2 work well together, however my iphone 5 does have gps capability but i beleive it does not allow the garmin glo when connected via blue tooth to override the phones internal GPS functions with the more accuare GLO device, so there is not much point in using the GLO with the iphone 5,
I plan to use the ipad 2 connected to the garmin glo for skydemon flightplans loaded on the ipad. I have a panel mounted Garmin 496 in the plane that can accept skydemon flightplans but you have to remove it from the airgizmo panel to access the micro usb connector which is a pain in the ass, so i will use the glo ipad 2 combo for vfr nav