This is the standard TomTom fanboy mantra... "Navigon ditched their US customers!"
What really happened is that Navigon realized that turn-by-turn GPS was moving to smartphones in the future and the PND market would be dead a few years from now. Garmin realizes the same thing, they just came out with a terrible phone as an alternative to creating only software. They still support their PND users, and anyone who says differently is a liar.
It must be convenient to simply dismiss any opinions other than your own as "Fanboy Mantra".
Take a look at US based PND forums Ex (http://forums.gpsreview.net/viewforum.php?f=38)
You will see quite a bit of griping about poor to non-existent response from Navigon USA. Not to mention that the company has completely stopped releasing bug fixes for their US based PNDs.
So I stand corrected. Navigon did not stop supporting US PND users, they just shut down operations and left a skeleton crew in place. I'd like my high-end electronics to be supported with firmware fixes and support at least till the end of the warranty period.
BTW Before you call me a fanboy read my other posts where I say that I use Navigon more than TomTom in most cases... unless I need to avoid a part of a route.