The biggest difference is if you have a slow guy in front of you, and they change lanes, the Autopilot would FLOOR it to get back up to speed. No need to blow up to 250kw just to get back up to speed. It was pretty unnatural. It's much smoother and more natural feeling with Chill mode on. It also seems to slow down a little more gradually now, not quite as extreme while in stop and go traffic. Just smoother and more chill. Changing lanes is also a difference. When changing lanes into an open lane, the thing would again, floor it to get up to speed. No need to... I am finding that when I engage Autopilot, I prefer Chill, but if I'm driving, take me back to normal.