This is a great app. It might not be as polished and have as much of that just-works-ness as something like Google Maps, but consider that the map is stored locally on your phone. You’re not telling Google or some other giant tech company where you’re going. It’s also very flexible. You can add “favorite places” like bookmarks, tell it to remember your parking space, and even add Wikipedia annotations to landmarks.
Along with privacy comes the fact that there is bound to be room for improvement - and you have control over that. If something is missing or incorrect on the map, don’t throw up your hands and switch back to Waze or whatever you were using before. Remember that OpenStreetMap is edited by volunteers, kind of like Wikipedia. All you have to do is go to openstreetmap.org and start improving the map. Any changes you submit to OSM will soon be available as an update to the maps installed locally on your phone. If you see a mistake in Google maps, all you can do is submit a request for someone else to consider fixing it.
Pros: Privacy, flexibility, ability to edit maps, offline navigation
cons: maps take up a lot of storage. My maps take up a total of 1.24GB. UI might be confusing to some because of all the options and some general rough edges. Calculating a route might take a moment longer since the calculation is done by your phone’s CPU and not a remote server.