My first drive on 12.3.6 showed no changes in basic driving behavior, as I'm sure we would all expect from a point relese. The differences I noticed were:
1. Vision Park Assist on my USS Model 3. I love the visuals, but it failed on the first parking attempt. I didn't care for the creaking and groaning as it regularly cranked around the wheels while stationary, and I won't be using it to park until they sort that out. In general, the assist is unwilling to consider driveways as useful space for maneuvering. I think the failed first attempt gave up because it couldn't move forward enough, despite there being driveway space it could have used. Later, when I got home, I noticed that the park assist doesn't even show driveways, presenting them as yard space with a curb right across the opening.
2. At the end of an FSD drive, the car will stop and tell you to press the accelerator to resume (but it stays in FSD). So you don't have to take it out of FSD to prevent it from continuing on its own after reaching your destination. They also added a curious arrow in front of the car in the visualization when you're at your destination. I'm not sure what that's supposed to indicate. My car parked about 100 feet from my house because there was no curb space at my house, and it apparently didn't want to stop in front of my driveway opening.
Oh, and I got a proximity STOP and chimes as I backed into my driveway. I sometimes used to get that when pulling out, so I guess my driveway spacing is just a bit too tight for its tastes.