Just hit 5,000km. Transmission still up shifts too early, but seems to be more willing to downshift with the slightest throttle. I think the adaptive learning takes a few thousand miles to learn your habits. My engine runs smooth, definitely feel it change modes around 3500 rpm though. My only negative is the brakes....way too touchy!!
I've been lurking on this thread to see where it's going and whether all understand the AI shift mode involved. Or even any of the Toyota shift modes ... I don't think the Adaptive Learning takes that long in all cases. From what I've researched, AI mode can be switched off for one thing, but when active, it is influenced not just by driver habits, but by road conditions and engine performance, among other things. It follows that the more complicated your habits, your driving environment and your upkeep of the engine, the more difficulty the system will have determining how best to attenuate transmission performance. Certainly, the engine itself is computerized, but in the TRDs, 3rd gen, a lot of the adaptive performance is tranny. AI is turned on when the transmission is in (D)rive and certain 4x4 features are not enabled. Using (S)hift modes turns AI off as well, but then as in a manual transmission, you have to do the work of shifting gears.
I've only got about 1500 miles on my TRD and have noticed only one transmission lurch earlier on, before it adapted to me and I adapted to it. When slowing to stop at a light, I noticed a couple times that the tranny would down shift giving an unexpected lurch as I crossed down from about 25mph to perhaps 10. That was annoying at best as I was still adjusting to the sharp braking. The supplied manuals mention the various shift modes, but don't give much detail. Search on Toyota Shift Modes and you'll find more, depending upon which search engine you use.
As of late, I am enjoying a smooth ride, smooth shifting and good mileage and economy. I've had only one lurch in the past couple weeks and the environment was unusual that day. It was very cold. I had to heat the car to defrost the side windows.
If AI gets to be too big a fit for you, try the S modes. You'll have to adapt to it as it starts in 4th from (D)rive and you'll need to watch that tach.