Well, just tried MCE 05
My opnion is that it can 'become' a great interface for the car, but not for most of us, and here is why:
The control buttons are way too small for us who r using 7" touch screens.
I can totally understand why you think is such a nice program with a 10" touchscreen.
but for in car use, you need bigger button so you can concentrate on on driving without trying to find those buttons.
It would be great if there is some way to change those player control buttons optimized on a 7" screen.