First solid long drive impressions, as three of us: Myself, my wife and my daughter, went up to the Toronto Zoo for our anniversary. We took the 401 there, so lots of stop and go, with periods of sustained 125km/h (~78mph) and due to how awful the 401 was on the way there, took the 407 (toll) back.
Firstly, you can tell the sidewalls are much softer than the run flats on turn-in, but bite is excellent, had no problem pushing it hard on on-ramps, stuck like glue. It definitely feels less "sporty" due to this, but that's not a complaint, as it was VERY firm before.
Secondly, they are incredibly quiet, which many people mentioned in this thread. That was a huge change, and a welcome one.
Thirdly, they don't tramline like the run flats did, which I assume is because of how much softer they are. Makes driving that much more relaxed, which is also welcome on a longer drive.
Looks like the tech and the Hunter machine got the tires well balanced, as there were no vibrations or anything, regardless of speed.
So, impressions so far: Positive!