I got this version pushed to my older 2017 MX a couple days ago. Don't have any of the strange things people talking about above.
I went out on 3 different trips about 20-25 miles and back home and mostly saying "WOW" (in a good way) the whole time. I was impressed at many of the things it was doing that I never saw before and had trouble with. In all 3 trips, I disengaged twice, but only because I wanted to take a different route or stop for something to eat. The drives were amazing after I've complained for years about all of the various strange things that FSDb would do. I'm finally starting to like it. Here are some things I noticed:
Roundabouts (traffic circles): A few of them near my home and finally doing it correctly. Staying in the proper lane, not speeding around them anymore and properly yielding. This has always been a problem for me, even in version 11 threads.
Not blocking intersections: Maybe this has been in there awhile and I just noticed, yet in ver 11, it wasn't working for me. In heavy traffic today even with a green light, the car stayed at the traffic light because it saw there was not enough space to move behind the car in front without blocking the intersection. Then when they pulled forward a bit and the car saw more space, it pulled through the intersection and behind the car that was stopped. Very cool. Just what I would have done.
Construction: Finally, it was handling the massive nasty 2 mile stretch of construction on a highway not far from the house. Changed lanes and merged perfectly at the right times.
Navigating parking lots: Twice I turned on FSD while still in different parking lots and it managed to slowly get to the main road without threatening people or getting confused. Never worked before in those areas. I previously had to get to the road before activating.
No Jerking steering wheel. I had some issues in V11. Last couple of days during all drives, VERY smooth turns.
The ONE THING I didn't really like but was ok with it was the aggressive start-off speed into a left turn from a stop sign.
It it perfect yet. Of course not, but I am super impressed for a change. I'll bet there are still situations where people have seen it do weird things. I just haven't seen it.... YET