So I've spent a few days with AC now and the comparison to PCars is an interesting one.
Visually I think the car models look better in AC than they do in in Pcars, but the environment and weather effects in Pcars put it ahead of AC in that regard. Damage looks much better in AC as well, but overall its situation dependent and I would give them pretty much a draw in that regard.
In terms of replays its again a bit of a draw as AC looks better, doesn't have the stutter than PCars does and has an excellent slow-mo mode. However it has a file size cap on the replay which means you don't get the full session at all, and it does suffer from screen tearing.
Audio wise AC is better than PCars, bu the margin is not a great as I had anticipated, and its does suffer from a few glitches, the worst of which is the menu music switches from speaker to speaker every time I change screen.
Career wise I prefer PCars by quite a margin, I like the structure of the race weekends and championship from the outset and the ability to start where you want and jump around at the end of each season.
AI I would also give to PCars at the present moment, AC is good, but lacks some of the situational awareness that PCars has, however I run PCars with the Crew Chief app, which does help. AC also has an issue at present in which the AI cars will pit for no reason which has ruined to many races for me.
Now the important bit. Physics and feedback. As an overall package AC is the winner here, however that's not without some caveats. When you compare the two between race cars, on a laser scanned track and with the wheel settings dialed in on PCars they are very, very comparable. However the road car tyre model for AC is streets ahead and weight transfer better modeled in FWD and RR drivetrains (to a large degree in the case of RR).
Feedback is very dependent on the track used and given that all of the tracks in AC are laser scanned it makes a big difference when compared to the non-scanned tracks in PCars.
Finally options, not something I would really consider but the difference between the two is night and day. In Pcars you can customise pretty much anything, and for many this was too much (mainly in regard to the controller and wheel settings), however in AC the exact opposite is with no option to map the buttons on the controller or wheel, no button box support, very limited ability to change the HUD layout and no button box or app support.
Overall I have to say that I'm glad I have both, as they do to a degree complement each other, Pcars will do me well when it comes to racing race cars and I like the time of day and weather options, however I very much doubt that the road cars in it will see much use going forward at all. AC has the better overall driving model (by a large margin for road cars), tyre model and for that alone its something I know I will spend a lot of time on (hell I've already bought the Season pass for it).
For me its like DiRT Rally and Seb Loeb Rally, they both have advantages and disadvantages, but both complement each other well.
What it does mean is that the job GTS has to do when it comes out is all the more difficult.
