Anything but Navigon
I found Navigon to be quite literally useless - I was absolutely unable to actually enter an address. The UI is completely squirrely - you have to enter addresses in reverse order: state, city, street, then number... only you can't type in a street, you have to pick from streets the system recognizes. And it didn't recognize ANY streets I needed to use, meaning I was never successfully able to navigate anywhere.
It's possible that I'm doing something wrong, but given that there's essentially no customer support, I found it impossible to discover what the problem might have been. Ultimately, I deleted the app and went back to plain old Google maps, which is free, and actually works.