Goodness knows I've been fairly critical of ac for many reasons, but the physics are very good. I don't like aspects of the ffb, but really it's hard to find fault with the physics themselves except in a few unusual or extreme situations, or at very low speed where they switch off.
Lfs physics are more rounded and the ffb is too imo, it's more cohesive, more "finished" even if it's not. Lfs is like a world where the physics are slightly different but you're "there". A.c. is probably more accurately depicting the physics of the real world, but I still don't feel that connection with it, probably because of issues like ffb and steering lag, even though I have all but entirely eliminated the latter, now. Certainly enjoyment of a.c is massively dependant on some hard work fine tuning lots of settings.