As of today i got about 1000km of small trips on Navigon and there's a few things i can say about it:
- Spoken directions are very, very good - best so far i've seen on a navigation app.
- Lane assist shows complete and easy to understand images.
- It excels on calculating and directing routes over highways and main roads.
However:
- Routes over secondary roads tend to be longer and more convoluted than they have to.
- Routes on tertiary and back roads is awfull and unusable.
- Drains battery like no other app i've tested.

So, it will not be my go-to app for navigation, but is surely one of the best!