We just got back from a road trip with 2019.12.1.1 in our X 100D (AP2/MCU1), Scottsdale AZ to Bryce National Park UT (Bryce Canyon Inn with Tesla chargers). We got right about 140 kW when our SoC was low enough, It didn't last long, out to 30% at one stop and lower at the rest.
AP has improved a bit since 2019.8.5 at least. When the lane widened due to an on ramp it would sometimes follow the left lane line, but about 50% of the time it would spring to the middle of the combined lane. Seemed like maybe it helped if there was a curve left, but who knows. I was impressed when left/right turn lanes suddenly appeared. Maybe it was picking the lane with no arrows painted on it, but it was pretty sure footed. It even picked a center lane when both left and right turn lanes appeared. I had to help once to get into a straight+turn lane. Otherwise it was perfect.
I tried NoA (Mad Max) with unconfirmed lane changes for two hours on I17 from Flagstaff to Phoenix, mostly at 80 MPH. The traffic was very light for 90% of the drive. Many times it changed lanes to pass a slower car before we had to slow down for it. That was especially impressive since it had to decide to change lanes, chime to warn me, wait about 2 seconds, turn on the blinker for another two seconds, then fairly slowly make the lane change itself. And it would return to the right-hand lane when the pass was done. But sometimes it ended up slowing behind another car and didn't change lanes. Or waited quite a while to return to the right, even with a car close behind us. So kind of neutral as far as usefulness, but a good start.
One other concern I had with unconfirmed lane changes was that it signals seemingly regardless of the surrounding traffic. It signaled once as a motorcycle was passing us, but still behind us in the target lane. Probably scared him/her since usually a signal indicates a lane change has already started, especially in very light traffic. It happened with a car as well.
I very clumsily aborted those two and a few other lane changes I didn't want. Like returning to the right not very far behind a slow car. I probably pushed the turn signal stalk too far, since I frequently just started signalling in the opposite direction. Between that, manually aborting a couple of changes by turning the wheel, and AP weaving around some wide lanes, I was kind of a crappy driver to surrounding cars. Reminiscent of 2017 and the "drunk" Autosteer. With more practice I can probably smooth it out a bit so that I'm not embarrassed.
For short periods TACC was slightly jerky for no apparent reason other than nearby cars. But mostly it was smooth. It handled all the curves of I17 and stayed well centered. Something that needs improvement but doesn't stop me from using it.
ETA: Holding the steering wheel with one hand hanging on one side of the wheel gave me no nags the entire trip and NoA was good with it for no-confirmation lane changes. I didn't have to do anything special for NoA lane changes.