What wheel do you have? AC seems to be optimized for low-end wheels whereas ACC works better with direct drive wheels. I played AC with a Logitech G29 and it felt really great with the right settings (+ LUT from wheelcheck). ACC with G29 was a disappointing experience for me.
Once I updated to CSL DD I put quite a bit of time into practicing ACC and eventually arrived to a point where I now think it's really great, and much better than AC. The FFB is so much more detailed and the physics are compelling. It took a couple of months getting fully used to the different FFB however, in the beginning even the CSL DD with ACC did not feel so good to me. I don't play AC that much anymore despite it working decently with the DD. I have noticed that after playing AC a bit more, going back to ACC my braking feeling is all messed up and takes some time to get back.
The point is, which sim feels the best to drive is a combination of hardware and getting used to the physics and FFB feel. Your brain needs time to learn to translate the signals coming from the game through the senses and different games are optimized to different hardware.
Also ACC requires more precise inputs to be quick than AC, you lose much more time with small mistakes.