Let me preface this by saying I LOVE my 85kw MS. I've never been that into cars, but this thing has made me a zealot.
However, as a major league techno-nerd, and after driving around in my MS in southern California for the last four weeks, I am greatly disappointed by the navigation system; ESPECIALLY traffic-based route alternatives.
I am at a complete lose why my two year old Droid Bionic using Google Navigation not allows me to scroll through route alternatives based upon distance AND traffic estimated time of arrival, but my brand new MS cannot. Google's crowd-sourcing traffic is, IMHO, an absolute killer app. I live in, arguably, the traffic capital of the world where there are always a plethora of other potential freeway routes, and Google Nav on my Droid is SPOT ON when estimating arrival times and suggesting alternate routes.
Unfortunately, the Tesla Nav is absolutely horrible in this department. Unless you are on a traffic-free route, the ETA is absolutely useless, thus even if it currently suggested alternatives that were distance-sorted, they would be useless unless you tried to eyeball the traffic colors on the map.
PLEASE Tesla, I'm back to using my smartphone for nav which kinda defeats the purpose. Oh, and while you're at it, please fix the ability to actually SEE the traffic colors that are on my route but are completely hidden by the gigantic BLUE navigation route line. Again, Google Nav does this brilliantly on the smartphone. Oh... and allow me to orient my maps as north or driver direction. Oh... and I want a pony.