I have to say I absolutely hate the Nav system in my 2012 335is. Maybe I havent figured it out yet, but I find it's just so hard to input destinations. The wheel character selector is so non-intuitive. Wish they'd have gone with a qwerty and used the tilt knob to move about.
The guidance itself is not very good IMHO. It does not seem to indicate the street name of the next turn, only that you have to turn soon.
Searching for POIs takes forever.
My 03 Acura MDX has a ten year old touchscreen Nav that's a hundred times better. And even my old Android phone had a Nav app that was way better.
All that said, I am happy I got the system, if only for the iDrive and how it handles audio, mobile phone, etc. I will probably rely on my iPhone for Nav tho.