Here's my two pence.
I drive a latest gen A5 and had an A6 fully loaded as a loan car while mine was having some maintenance servicing work.
Let me tell you, I HATED the A6. It's one thing to not be able to fully control the entertainment safely while driving. Like okay, just wait until/ if you hit traffic to change it, but when your main functions of the car other than the hazards, such as temperature control, seat functions or demisting the car windscreen or rear window rely on super low down buttons with at least 20 of them thrown together, then it is a recipe for disaster.
On my A5, I can not only control important functions, such as demisting and getting myself, the driver, to a comfortable temperature, I can scroll wheel or press my way through pretty much every other function of the car. Start making an adjustment to music I.e. scrolling, drive and then continue to make an adjustment when it's safe to do so.
As a side note, as some other posters have mentioned, my car also does the whole steering in lane for you, and keeping a safe distance, cruise control etc. This is all nice and certainly reduces the fatigue while driving, but it definitely does not make you a better driver. Sometimes you have to be prepared to step in and correct mistakes the system will make.
I absolutely detest touch screen only controls in cars, and I'll be pretty tempted to move over to Mercedes for my next car because of it. Audi be stupid.