I use my $99 Garmin and thus far have been perfectly happy. Never owned NAV in my previous E46 or current E90 - and on the fence about getting it for my F30 purchase. I certainly don't think it's a must-have option as there are alternatives (like the Garmin, Iphone, Android, etc). It might be must have for other parts of the tech package though.
F30 2013 335i xDrive BSM :: 8AT :: Sport Line:: Tech Package :: Anthracite :: Heated Seats
E90 2006 325i SG :: steptronic :: xenon :: power/heated seats :: comfort access :: sat prep :: poplar
Mods: Chrome Exhaust Tips
2013 RX 350 Mica Blue
Retired: 2001 325i
Retired: 2003 TL 3.2