It's clearly a very competent sat-nav, but there are, unfortunately, plenty of areas where the Navigon can't match TomTom's market leader. It doesn't have an equivalent to TomTom's IQ Routes, for instance, which uses historic data about average road speeds collected from TomTom users (rather than speed limits) to calculate routes.
Neither does Navigon have an equivalent of TomTom's map corrections feature – MapShare – which allows you to correct errors in the map and share other TomTom users' corrections.
You don't get an FM transmitter for piping sound through your car stereo. And it's not as responsive as the Go 730 either. During address entry, tapping letters on the onscreen keyboard results in a short delay. It's nothing serious, but it's enough to become mildly irritating when planning complicated, multileg routes.
I could go on, but you get the picture: while Navigon makes a decent fist of competing with the TomTom Go 730, even beating it in some respects, overall it's simply outgunned.
That wouldn't matter so much if the price was lower, but alas it isn't. The 2150 Max costs £220 plus £40 for the traffic subscription. That's pricey for a sat-nav in today's ultra-competitive market and, importantly, no cheaper than the equivalent TomTom Go 730 Traffic. It may be good, then, but given £260 to spend on a sat-nav, we know where we'd spend it, and it wouldn't be on the 2150 Max.