[grommi]

Yes Paul, if you ask 10 people about one film and one developer, you get at least 11 opinions. You can collect data, but then you must make your own experiances and decide. Because you liked the old TechPan, I would first try the "new" ATP. It's most probably Aviphot Pan 25 or something very similar from Agfa-Gevaert/Belgium and their production quality is excellent. 300 lp/mm at 1:1.6 contrast is really hard to beat. If I wouldn't have a nice stock of old TechPan that I like so much I surely would try this one.

Best - Reinhold

Edit:

" CMS 20 is orthopanchromatic, more sensitive to blue light. I don't have much experience with ortho films, will these blow out blue sky at high altitude ?"

Yes, it will, even at regular altitude. If you want great sky rendering and seperation of clouds then a superpan film would be my very first choice - maybe even with a red or orange filter. If you want athmospheric "character" with more haze in the distant, then a ortho or orthopan film would be the choice. So far my first-grader knowledge.....

Edit2:
"but I want to have control over my process first so that I don't have to think about all the time." -> use film and gear that you know inside out.