I assume that because you are posting here you are looking at one of the early C8s rather than a late C7. If you put the software issues to one side then the C8 is a great car. I had an early 2.0TDi and currently have a 2.0TFSi, both Avants.
On a 2018 car you need to check that it has had the transmission fluid changed at 38k miles or 4 years if the mileage is lower, since the S-Tronic box is very sensitive to this. The car only comes with 3 years Audi Connect from new, so if you want to continue to receive real time traffic updates, get updates to maps and use the features in the MyAudi app then you will need to renew the service with Audi.
Now to the software issues, which are well documented here and on other forums. Your experience will depend on what software updates have been done on the car, and getting those going forward would be one of the reasons for staying with Audi for servicing, their fixed price deal for cars over 3 years is fairly competitive compared to Audi experienced independents. Key issue I faced on the diesel car was that if you switched the engine off and then back on again shortly after the camera based safety systems would not reinitialise triggering a warning on the DIS. Switching off and leaving it for about 10 mins to let systems shut down properly seems to be the only cure. This was of course totally random as to when it would happen. Also waiting for it to initialise after restarting before driving seemed to (but may not!) address the problem. Software updates may now have addressed the issue. A car of this era will have the MIB-2 MMI system which seems less bug prone than the later cars (2020 on) which have MIB-3.
The Tech Pack which gives the Virtual dash is a nice to have in my opinion, neither of my C8s have it and I do not miss it, despite having driven loan cars with it. I would avoid cars with the Sunroof, it requires regular maintenance and the stories of leaks, admittedly more commonly on the C7, would make me keep clear of it.
I think that probably summarises my experiences, I had 2 C7s before the C8 and the C8 is definitely an improvement on the C7. I can't comment on towing but the C8 2.0 engine is 204bhp which is more than enough for normal driving. With a strong bias towards commuting and short journeys I got about 45mpg, but over a long motorway run I could see over 60mpg.
