In my experience a dedicated GPS receiver is much more accurate than an IPad or phone. It also has better battery life for remote use. I also recommend a receiver that is compatible with US and GLONASS satallites for better coverage especially under tree canopy and in canyons. US satellite orbits are more oriented towards the equator due to where where the military has been operating. GLONASS orbits are more oriented towards northern latitudes because of Russia's operations in the Baltic Sea.
