Bimmer navi is certainly horrible like most every other navi that isn't made by Honda/Acura. I can't stand any of them having used BMW, Volvo (really, Volvo?), Lexus, Infiniti...
Honestly, I don't bother other than using it as a map to show major roads. If I'm in need of directions, I always just use my Android Google Maps navigation that is terrific. On the new Androids, it even automatically switches to Street View as you pull up to your destination. Amazing execution by Google that should be a no brainer how-to for luxury cars. Garmin is pathetic in comparison IMO.
Destination entry and voice commands with BMW is a waste of time. In three years, I can't think of a single successful attempt at a voice command working correctly. Acura does a decent job, but tv commercials all make voice entry an overrated feature on any car.
Use your phone Google Maps before you leave.
My two cents.