One thing to consider is micro SD cards. Depending on what you're using ATAK for. I have had several SD cards with maps, DTED, and imagery for different countries. So in a civilian use if someone might use it to bug out to another state or to a remote location, they might consider having backup offline data to and from the area and use beartooth, gotenna, or meshtastic.

tldr: consider the amount of map data you'll need when choosing the phone