the films are now developed. Two rolls shot @ EI 400 and one @ EI 250. Developed in Xtol, Kodak times, dip and dunk machine.
Main difference seems to be better grayscale and shadow detail. At EI 400 it seems like the pictures has a tendency to look slightly flat. But that may well depend on my photography skills. I have only been at it for about a year and a half, so I still have lots to learn.

Anyway, it was an interesting experiement. I wonder if the Tmax 100 would render the same improvement with overexposure. I seem to remember a roll of the old Tmax 100 exposed at EI 50, developed in Agfa Rodinal 1+100, with slight compensation for overexposure (10 or 15%). Those negs looked great!

Anyway, drifting away from the subject. Thanks for your input, it helped me make a good decision in the developing process. Maybe I can learn to like high speed films after this. I actually find the results on the 250 roll quite encouraging and useful, despite the grain.