AP1 owner here, been using it since the day it was released in October 2015. Put me firmly in the "it makes driving easier" camp. (Note that I have never driven or ridden in an AP2.0/2.5 car.) Random thoughts and things I've learned from the past 2.5 years...
o It helps immensely to understand the components of the AP hardware and software and what their limitations are. I am completely aware that one needs to research this.
o The "less fatigue" effect of using AP (which I will use to refer to the combination of TACC+autosteer) is both mental and physical. Mental because it's less effort to drive, and physical because my arms, hands, legs, and feet are not making micro-adjustments on the steering wheel and pedals. The effect is real...I've done long drives and not felt wiped out as I would have in the pre-AP days (both in my Tesla and in other cars).
o With AP engaged, it's easier to supervise AP driving than it is to do the driving myself. I can devote more mental attention to planning ahead rather than worrying about staying in the lane, not running into the car ahead of me, and so on. Always maintain situational awareness, but one can think about planning the drive a little more strategically and less tactically.
o There are definitely things that AP doesn't handle well. Very curvy roads, hills, driving into the sun, construction zones, accident zones, tunnels, and bridges with narrow shoulders are all places where I'll opt to take over control from AP before it gets in trouble. This is one of the key things...realize where it's likely to run into problems because of tolerances or due to unpredictability and take over control of the car before there's an issue. Actually, it's probably better to start out assuming that it doesn't do anything well, and then back off from that as you gain confidence in it.
o Remember that AP (at least AP1) is intended for driving on divided highways/freeways. I don't use it in town, ever. I think that people who do this are reckless. I'm not comfortable using AP on undivided roads, and I get nervous watching YouTube videos where people do this.
o At least one hand on the wheel at all times except for very brief exceptions. Not because of the nag timer, but because by keeping a hand on the wheel, I can feel what the car is doing. Every so often I'll gently wiggle the steering wheel...I want to feel the resistance that says that autosteer is still active. (I keep that habit because I have had a couple instances with TACC engaged, no autosteer, and have forgotten that the car wasn't steering itself!)
o Feet away from the pedals except when I'm getting ready to take over, to avoid accidentally nudging a pedal.
o Due diligence and common sense always. If I find myself in a situation where I'm not comfortable with what AP is doing, or I need the car to do something that AP can't do, I won't hesitate to take over.
o I don't know how much training Tesla gives new owners at delivery time (my car pre-dates the release of autopilot software, so that wasn't a factor). But IMHO, a one-hour delivery appointment with the car sitting in the delivery bay can't adequately explain autopilot to someone who's never used it before.
Bruce.
