Mapfactor is probably the only Android navigation, which doesn't download maps on background. This means that I can not use my phone while the maps are downloading, which might take quite a long time.
Please implement a background map downloading service.
For me the download is always canceled if I return to Mapfactor. I have a lot of RAM (4GB) so the download should persist even without a service. But whenever I leave the application and then I return, I get back to the main screen and if I open the map download menu again, I can see the maps are not downloading anymore.