The 3D maps use high resolution images of the WorldView satellites so you can expect absolute clarity of the places you navigate. Also, along the way you can read detailed day to day information and view pictures of trek routes such as Lukla to Mt. Everest Base camp, Khumbu icefall, Lhotse flank and Mount Everest Peak
One of the popular telecom service providers in Nepal, Ncell, already provides 3G service in the Mount Everest, so you can expect to stay connected with your iPhone.
For those people who want to save some data charges Mount Everest 3D pro can be downloaded for $5.99 which will have offline maps and information on Everest trek routes.
Here is direct link to download Mount Everest 3D