I keep mine on 7. If someone wants to change lanes, I let them. If they get in front of me, that’s OK. If they stay in my lane and if they are going where I am going, they are going to delay me by a car length. At 70, a car length is just over a tenth of a second. If someone uses a blinker and needs to change lanes, I let them in. I can afford the time a car length of delay causes.
I like to leave some reaction time when using autopilot. It’s not like a Windows glitch that simply freezes with a blue screen while I’m at a desk writing a letter, this is real, I’m on board a computerized machine moving along at 102 feet per second and it is running beta software. That’s 1/9 the speed of a 45 cal bullet. It’s 1/11 the speed of sound.
I like to use it. I like to watch it. I don’t quite trust it, not yet. I don’t want to bend my car, or worse, because there is a non optimal line of code somewhere.
I think the phantom braking is a problem. The car suddenly hitting the brakes and dropping the speed 10 MPH or so won’t be good if there’s a driver behind following too closely. It doesn’t happen often, once in a thousand miles or so, but then, it only takes once. People in general aren’t aware of the sudden unexpected braking. On my last trip there was a semi following me closely enough that the ultrasonic sensors in my back bumper were displayed. A few miles later, there was a phantom braking episode. If that trucker had been tailgating then, I think things would have gone badly.
Anyway, I leave it on 7. If there was an 8, I’d use that.