Hi Stevo
I came from C7 RS6, it was coming up for 2.5 years old and only covered circa 25k, the C8 wasn't due out for 6 months or so, and opted for the E63 rather than an M5. Initially, i was impressed b the dealer who gave me the full beans test drive experience and was wowed with sideways around a roundabout fun, it seemed mighty quick.
The reality is once ownership took hold, it cant get the power down and is very tail-happy. You cannot drive on the standard PS4 after about September as it slips out over 30/40mph in non spirited driving in comfort


Compared to the RS6 I missed the grip and surefootedness, the Audi was very predictable at the limit, the Merc was like the wife, no idea how it would react the day you drove it

Moan over
The fecking sound of the beast in race mode I will miss, fan-fecking-tastic. It's like it wants to kill you. Nothing like an AMG for it - Awesome
Great fun to drift - whether you wanted to or not just had to be very conscious on road widths when making progress
The dash - well that I am gonna miss, you have about 40-50 options, two dials, one dial, each side has 3-7 menu options in each menu, very customizable, loved it. The Audi virtual cockpit has a lot to learn, although I need to spend time with it to give a true comparison. I believe the newer version has the updated touch screen which will make it even better.
The performance seats were great even on 3-4 hour long haul drives.
Overall I have enjoyed ownership, a very understated car when going to meetings, it looks as boring as hell until you start it up. The RS6 had a look that people would ask what it was, rather than a full Q car
I hope this gives you a bit of an insight into my experience
Bush