and maybe not as simple as assuming that newer is always better or more desirable.
Having said that, I do think the new Patek chrono movement is beautiful, technically and aesthetically. But I also feel the same about the Lemania. There are certainly technical innovations, but when I have played with both 5170 and 5070, I don't notice any improvement in the feel of the new chrono movement. To the contrary, at least on the examples I have held, the 5070 has a smoother feel, and this is important to me in a chrono.
So far with limited "in the metal" experience with the 5170 (and none yet with the 5270), I don't see any aesthetic improvement in the new watches, in fact preferring the older Lemanias. One potential significant plus of the 5170 vs 5070 is the better size for my wrist, though these days 42mm does not seem nearly so large as a short time ago. And the 5270 could be going in the wrong direction, adding a mm or so over the 5970.
Not to raise any unfounded issues, but comments in this thread are not the first I have heard of possible reliability issues with the new movement, which I assume are to be worked out in time, but would give me some temporary pause.
Looking at the "minor" issue of price, it is hard to swallow a simple YG chrono at $76K or a WG chrono/perpetual at $159K (if memory is correct). So if at equal price, maybe a stronger case could be made to jump into the new movement. As a complete package including price, this is a big commitment for a watch which could be around for a while, especially when the jury is still out.
But if I had to make a guess, as Patek chronos both the Lemanias and in-house movement watches will be very sought after for a long time, and these forums will be filled for years with 5070 vs 5170 threads..... And soon 5170 vs Datograph threads, etc...