well, I bought a 350 LM here in the UK after good reports in the motorcycle press. Good navigator and features. Only trouble was that the unit would not charge in the cradle. Garmin sent out a replacement, and still no charge. Would only charge through the usb cable, which you cannot use in the cradle of course. So as a motorcycle nav it was not fit for use.
I had to go to my BMW dealer to get a report to say it was not the motorcycle at fault even after I explained it was wired straight to the battery ! (customer service, Halfords). The wiring was correct and showing voltage at the pins, so the BMW report said it must have been the unit.
I eventually managed to get a full refund from halfords. Not sure what to do next, any suggestions on a reliable unit (zumo 660 ?).
Back to using maps at the moment !