With Tech Pan, the issue (for me at least) is it's too slow and would require Technidol for proper processing.

Same with the old Kodachrome 25 vs. Ektachrome 100. No doubt the Kodachrome is a better stock for color rendition and "non-grain" in comparison, but too low in sensitivity for much beyond hot air balloons, still life and studio portraiture. And then there's the processing issue.

It boils down to what the final product needs to be, I guess. And I've mostly been "deadline oriented" with my work.

Hot air balloons, LOL. I've never been much of an action photographer so the 50 ASA hadn't been an issue. I never tried to push the film, wonder what that would have done.

"Push processing" generally makes grain more obvious and builds contrast. B&W stock and Ektachrome could be pushed, Ektachrome could be "hypersensitized" for astral photography using a pressurized tank and nitrogen. Quite a process. I've known a couple guys who did that, they had some amazing results. Both used Questar 'scopes and "clocks" for long exposures, as well.

With Kodachrome you were locked into the ISO/ASA of the emulsion.