I don't have a D850 yet, but use all the PCE lenses on a D810.
The 19 still has some distortion, so the movement tab in Capture 1 is very helpful. It's a bit cooler color-wise than the older PCEs. Overall, it has a great look to it - great color, contrast and very sharp. Filters are an issue, I still need to get a polarizer.
Going back & forth between the new & old style of PCE controls keeps you on your toes: the rotation locks are in different places, and worm-drive vs rack & pinion shift is different.
Looks like the D850 will have less interference between the prism & 24PCE.