I recently did a round trip from Saratoga to Sacramento (128 miles each way) with my 8 months old Model S. This is the first time I used Autopilot most of the way … even in heavy traffic. Here are my observations. It was mostly smooth and work as expected. I had TACC [Traffic Aware Cruise Control] set at 72 mph. When the car in front slowed down, my car also slowed down. When a car cut in front of me, it would slow down accordingly – evenly or abruptly depending on how hard the car cut in front of me. [It was a bit unnerving at first since I was not the one putting on the brake … but it did its job]. The AS [Auto Steer] feature worked well with a few minor complains. (a) I kept at least one of my hands on the wheel all the time. There were a few occasions I had accidentally turned AS off (by holding the wheel too tight and countering the AS steering). There was no audio signal to tell me that it had gone off. I only realize it was off by looking at the dash. This can be a potential future improvement. (b) There were a few rare occasions when I was in outside [slowest] lane when I came across a Y shaped exit. AS hesitated. Not sure how the algorithm can tell which is the one to go straight [not until AS is integrated with mapping function]. Guess this is where you really need to have your hands on the wheel. (c) My wife [on the passenger seat] complained a few times the 18 wheelers on the next lane were getting a bit too close for her comfort. Not sure if the algorithm will keep the car always in the center of the lane or will make adjustment base on how close the next car is to mine.