Just passed 1000 miles on my Ltd. The only issue I've run into was yesterday when I tried to navigate to a previous destination.....it sat on computing route (in my right 4" LCD screen) all the way home and continued to "compute the route" today.
The issues you might've noticed are software related for the most part. Though they can be annoying, they don't affect everyone and will be addressed in a software update; hopefully sooner rather than later.
I turned in a beautiful 2008 BMW 335i for this car and have no regrets.
Update: I was able to work around the permanent "computing route" hang up by using voice commands to request a different destination, canceling the first one. Using the touch screen wouldn't cancel the route calculating and telling Sync to cancel current route didn't work either.