I can say this.
I gave up on trying to read the manual. Its too friggin thick and about the most poorly written manual I've ever seen.
I haven't even got a clue as to what all the silly buttons do for the stereo, way too complicated for my old brain. When I do use the stereo, which is rare, I just turn it on and use XM ... AM/FM is a vast wasteland (IMO).
That said, we figured out how to use the NAV to get us home from the dealer without too much hassle (not like we didn't know where home was

) and used it several times since ... yeah, fairly intuitive
However, we also have a Magallan 760 or something like that and its FAR easier to enter new destinations and extremely user friendly. Aftermarket GPS is usually much better than any OEM GPS in a car (and a whole lot cheaper).