OsmAnd Maps & Navigation is a free map and navigation application that utilizes OpenStreetMap data.
Ranked in these QuestionsQuestion Ranking
Pro Works offline once the maps are downloaded
Pro Based around crowdsourced OpenStreetMap data
OSM provides a map editable by everyone; just like the web-based encyclopedia, Wikipedia.
Using a community edited map allows one to correct isses they encounter. Combined with the monthly turn around, these edits are added for navigation quickly.
Pro Excellent general map viewing
Sometimes one needs more than just navigation, they have a need to view a map or specify a specific route. OsmAnd provides a very nice, detailed map. This can be good for seeing what is around you or showing a place you are talking about to a friend.
It also provides a means to add waypoints on the map which can be used to dictate a specific route (not simple enough to do routinely).
Pro Routinely updated maps
Utilizing the community driven OpenStreetMap data has allowed for monthly publishing of new maps that the user can use. Though that doesn't necessarily mean the map data has changed.
Pro OpenStreetMap contributing made convenient
One can also utilize features to contribute back to OSM. This includes reporting a bug or adding a POI. This feature doesn't require an internet connection as the points can be uploaded latter upon request.
Pro Helpful lane guidance
Lane guidance can assist in deciding if one should stay in the right or left lanes. OsmAnd provides detailed information on the number of lanes and which are valid for your chosen destination; based on the data available it may show too many or too few lanes.
Pro Contour lines enable understanding the terrain
Through the use of an additional plugin OsmAnd Maps & Navigation is able to utilize contour lines on its maps which helps view the landscape and terrain.
Con Slow rendering
It can take some time for an area to be rendered. This tends not to be a problem during navigation since only a small area must be rendered as the map moves, and this area isn't immediately needed; though likely a bigger issue with smaller screens.
Con Poor navigation interface
The interface is not the most intuitive, though is continually progressing. It doesn't provide a 3D view like many navigation apps.
Con Near impossible to scroll through map
Due to the slow rendering (already mentioned) it is near impossible to scroll through OsmAnd's maps. You move the map only slightly and it takes ages to redraw all vector layers.
Con Being based on OpenStreetMap data can be lacking
The use of OSM also has the drawback of many places not getting the attention needed for updates. Depending on the geographic location OSM may have the most detailed maps or the most bare/outdated map.
Con Terrible address data
This is a limitation of OSM's data, but it is unreliable for locating an address while offline. Even with internet it doesn't appear that it can locate most addresses.