Put me in the camp that believes this is not only a total waste of money but also terrible to look at for your X.

Why would you want to strap on that ugly thing on the dash when you have a built in screen?

The BMW Navteq navigation does not always take you on the shortest route because of preferences and traffic. I do find the traffic info very helpful even though I know where I'm going. It shows me which roads to avoid.

There are concerns about sometimes it not being up-to-date, but other systems (garmin, etc) have the same issues.