The Garmin Map Pilot is currently available in several Mercedes-Benz models including the C-Class and CLS-Class. (Fun fact: The Garmin Map Pilot is standard on the CLS400 and the hard-drive system is in the Premium 2 Package.)
I have had a little hands-on experience with this system and find it to be very intuitive. Here is a new video from Mercedes-Benz How-To Videos page on how to use it.