The NAV in our X3 is the WORST system I have ever used.
1) Driving down an expressway it will have us exit and then reenter the same expressway.
2) Take the "two right angle" streets instead of the "hypotenuse" -- even when the side streets have stop lights and the "hypotenuse" doesn't
3) Completely stop navigating in the middle of route
It is fine for driving long distance on the highway. It is WORTHLESS for routing around town.