Please, pretty please, tell me how you got your garmin or BMW Nav working with a mac? I am having a prolonged nightmare with my Nav6 and Macbook air. In contrast to your experience, my Nav6 was awful in Spain. Any guidance would be much appreciated.
Can't help with the Mac stuff but I am sure Wapping and Co will be along soon to help. But saying the device was awful in Spain has nothing to do with what sort of computer you use. Firstly have you updated the maps and device software? Possible not if you can't make it work with your Mac. Once you have that sorted you can use Basecamp (free dowmnload from Garmin) and connecting your device will show if there are update available. Given that the Garmin maps are reasonable accurate any problems you had are I am afraid likely to be down to operator malfunction. One of the joys of these devices is they can be set up to suit a variety of needs, The downside of that is if your settings don't match your expectations you will find the device does what appears to be very strange things. Mostly this is because you have (unwittingly) told it to do just that! Take a look at all your settings, anything is possible, i had one guy willing to throw his Garmin under a bus because it was "bloody useless" It turned out the device was set to "Off Road" route calculation and was therefore trying to route as near as possible to a straight line, Simply changing that to "Faster Time" solved the problem (and keep me it beer for days)
You can then start to learn how to plot routes in Basecamp, a whole new world of fun!
Good Luck
John