We use the free Mapfactor GPS Navigation (MGN for Android) and have found it really good. Country maps are also free and multiple can be downloaded…really dependent on the storage capacity of the device. It is especially useful when travelling overseas. It is also updated regularly by users which keeps maps current, however, can chew up data allowances (e.g. Australia mapping is about 0.1GB) if one decides to update over the mobile network. However, map updates are notified automatically and are updated manually (by going to the map download area).
Recently on our trip to Chile, we also used a car GPS (Mazda and Hyundai) and also downloaded (WIFI) Google Maps for the area we were staying. We used Google Maps only to travel to features which were not present in MGN.
We found the road coverage and accuracy of MGN superior to Google Maps and the in car GPS. Google Maps possible can second out of the three but often didn’t have the small rural roads often which can be used for ‘shortcuts’.
The in car GPS often was in the nether nether with our location an arrow on a featureless/blank screen.
The only downside with using three GPS options was the nominated speed limit in MGN was often different to the in car GPS, which at times both were also different to signed limited (if and where they existed…in Chile off the motorways/highways, signage can be limited to non-existent).
In relation to ease of use, Google Maps was the easiest to use, then MGN/in car GPS were possibly similar.
Something which we also found useful with MGN, is when we had wifi we would search for features we wanted to visit using the in app google search function and then used this to create waypoints within the app. We ended up doing this particularly in rural areas where Google Maps and the in Car GPS mapping was non-existent.
The other big advantage we found was in China where Google Maps is offset by a significant distance (estimate by about 200-300m) if one downloads a map before leaving…or as google is blocked, it can’t be used within China. We didn’t have any problems using MGN in China and it was reasonably accurate (less offset than Google Maps).
Only downside of MGN is it does chew through battery power relatively quickly.
Voice commands with MGN we also felt were better. They provide more and greater distance notifications to turns/intersections and such like. Its voice was just as good as Google Maps.
A downside for Google Maps is it can be fiddly downloading maps for long journeys as it limits the area of coverage that can be downloaded in a single map section. MGN has map for whole country in its download.