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I've never used Navigon, but it sounds like a good alternative. TomTom would be my first choice, in part because I used TomTom GPS navigation for years before there were smartphones, and it has always served me well. It updates maps automatically, and is very similar in use to the GPS devices that are built into cars. However, there are a couple of downsides. One is that is cost $50 to purchase, and a yearly subscription update costs $20. A new development that is a much more serious negative is that in the rush to get away from all things Google for the iPhone, TomTom no longer uses Google to search for places, it forces you to use Facebook search. Facebook search!?!?! Really!?! Other then that it is very solid, but that forced Facebook connection could be a deal breaker.