Navmii GPS World (Navfree) vs Avenza Maps

The quality of images in the app are sometimes not the best . It is caused by some form of conversion, which may save room but limits the apps looks.

Even though the maps are free of charge and some of them are official park maps without copyright issues, the app still refuses to store them on the SD card, so the map storage tends to take up far more internal flash memory than any other app.

Searching for map files is very frustrating as the map search only shows the center point of each map as a pin, so you can't see whether the map includes a point you're interested in, and since there are usually many historical maps of the same location, they produce many pins appearing on top of each other. You have to download each one and open it in order to see what it will look like, rather than previewing them in the live display. Good overview maps will appear as pins in random locations, while there will be tons of topo map tiles everywhere else

It supports USGS topo maps, for instance, but if you walk off the edge of one, you have to manually load the adjacent map, which is a hassle. It would be nice if, like other apps, you could select "USGS topo" as the map source, and it would automatically show whichever specific map your location is currently near the middle of (since the USGS maps have margins and legends, etc.)

You need to plan ahead and download a map for each park or region you're going to visit before you go offline.