I'm considering a new A4 Convertible, an A6 if I can stand the new nose, or
a two year old A8 or three year old S8.

The use will be for daily commute (40 miles round trip), carrying four
adults a fair amount of the time. I'd like a fun driving experience if
possible, but that takes a back seat to reliability and professional look.

I've driven the A6, and S8, and my partner has an A8.

I currently use a 99 S Class Mercedes as my daily driver, and find it too
large, ponderous, and poor handling. It is the 420 model, with the smaller
V-8 driving a 4700 lb machine, so it isn't great on acceleration. However,
it is well built, solid, and cruises with the best. Looking for more fun
and handling, without losing all of the creature comforts.

Would love opinions from people who have actually owned and driven these
specific models.

Thanks.