New 2013 535i owner here. First BMW.
Was very disappointed with the nav. I assumed (incorrectly) that when you pay this much for an auto, the nav would be equal to or better what I have on my $200 iPhone.
The worst for me is the constant "bear right" and "bear left" instructions when going straight on a freeway. After a few miles, this gets downright annoying. It seems like it sees every curve in the freeway as an opportunity to tell me to "bear" in a certain direction, but looking at the map it doesn't necessarily seem to match up.
This to me is a serious bug, and not just a simple annoyance. When I have hundreds of miles of driving on a long freeway I don't want to keep hearing "bear right" every minute.