Late last year I drove a W164 with the latest NAV on it (I had it for several days, went on a family thanksgiving trip) and was actually frustrated at how unfriendly the darn thing was. The W164 system is extremely well done - nice color, voice, options, features (maybe too much?), etc. However, it's so loaded with data and features and options and whatever else that the engineers have yet to figure out how to relate all that info to the user in a clean way! The W163 NAV has been dissed several times as old and cumbersome, but is that really true? Compared to what? On my 163 system, I can simply type in a phone # and, bingo I have directions to where I'm going. On the 164, I had to go through several menu items to get the options I wanted. Going to a previous menu wasn't so obvious either - in most cases, I had to start all over again. I don't think it was because my brain was wired for the 163 system because I had the car for a long time and I made an effort to understand it. So, what do the xperts say?