Offline capabilities are fine. Works good in the field without service. The only issue I have with it is that it lacks good zoom capability. If you zoom in to get a more accurate location on most of the downloadable maps. The map image disappears and you see map tiles that say "image not available." This is a real problem in my book. Especially when your location may deal with property lines and GMU boundaries. Showing my location that could be 1/4 mile in either direction of a boundary, can get you into trouble. They will tell you there are a few maps that will zoom in closer, but they are not the good maps from the forest service that actually show all of the trails ect.
Another problem I've seen is again with the zoom. If you have a normal size phone, some of the lettering on the maps are small. If you try to zoom in to read words or numbers better, thinking it will make it bigger. It doesn't. It readjusts all of the overlaid letters and numbers and they become small again before you can read it.
In my opinion. It's good to use as a back up to a better GPS app like Gaia GPS or for just general location and viewing public/private land.
When it comes to your battery life. It should be fine. I just keep my phone off or in airplane mode until I need to get my location. Keep your screen brightness low. I used it on a 5 day high buck hunt last year. My IPhone battery lasted 2 days. I carry an extra battery pack that will charge my phone to 100% 4 times. I also pack a solar unit that will charge that battery pack. If you do something like that you'll be ok.
