Just to counterbalance this thread for some readers who want information on Pilot Assist:
I LIKE IT!
I noticed that I can see further than the radar. I can see where the road turns, far ahead, and would have started turning sooner. I could see that the double yellow veered left to make room for a left turn lane. But, as we said, it's learning.
The side awareness has greatly improved. The braking has improved. The following has improved. I drove 60 miles today with it, and it generally did as well as I might. Yes, it veered a slight bit when the left turn lane came up, then realized and veered back. I see human drivers do a lot worse. Yes, it might lose one of the lane lines, but it would follow the other side just fine until it found the first one again. It stayed in the middle of the lane quite well. When it started having too much trouble, it asked me to help out.
It noticed vehicles near me, guard rails, bushes, even. It did not veer from them. It followed a car doing 60 mph to a complete stop at a signal (it doesn't read signals or stop signs) and then back up to speed, with no help. It veered at an exit, but only slightly, and quickly came back to the lane. It had no trouble changing lanes with no other help than holding the signal until it was well near done.
Just as a reminder, it was recommended that this was for long stretches of highway. To me that means no turn lanes or driveways, etc. Tesla also said that we were supposed to keep our hands on the wheel and watch. No problem if you do that.
I plan to use it mainly on long, boring highway trips (4 hours to LA, 900 miles to Phoenix through "inspiring" desert scenery) and it is made for that.