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Osmand is quite good. My experience is that you have to understand the logic of the search function. But granted, it can be much improved. The navigation for pedestrians or cars is sufficient for my needs too. However, the route calculation is sometimes ridiculously long. For example, if you want to go from one city to another and avoid highways it sometimes takes like 15-20 minutes (seriously) to calculate that route. That part sucks.
Is Organic Maps good for car navigation and for pedestrians?
As for public transport: You might want to try Transportr. I used it in London and many other cities in the world and it is doing a really good job. Just make sure you take the apk from their github repo. It's outdated on F-Droid.