It uses openstreetmap data, except for our country and slovakia, where it uses its own map data. Although it has a some features aimed only at our country it can be used by anyone around the world without problem. In comparison to google maps it’s much more usable for hiking and cycling thanks to it’s less dull map graphic. Since the app is owned by a profit company it requires you to login to be able to use some of the basic features, like saving routes or recorded tracks, which is a pity. I am not really fan of Seznam (company behind it) and their services, but their maps are probably their most useful and well-done usable service. It has a web version too: en.mapy.cz. when it comes to navigation it has no traffic information except in our country. I would say that the navigation is average, but generally works well.