Interesting I stopped reading this thread. I happen to use both..... I have a Garmin that I fly with for rental cars and loaner vehicles. I will gladly take the in car NAV if available. For the upgrade price it gives me complete integration into the car. Has anyone tried to do all voice command navigation with their Garmin while driving? Some states issue a ticket for touching your nav and driving!
When Garmin comes out with a 7.5 inch Nav that seamlessly integrates with my car and displays turn information in the cluster, I will then compare the two on equal footing. I don't like having any part of my view obstructed if possible and I love seeing lane assistance messages right in my cluster.
For me it matters for many it does not but a stick on / clip on Nav doesn't compare to in vehicle integrated systems. You want to get a Garmin with lifetime updates and save the money... great, I have one of those and they are good. But I am fine with updating my in car NAV and paying for it every couple of years. Beside Chrysler usually will send out a free update in the first couple of years anyway.
To each there own, nobody is making anybody buy anything