I checked Windiff again, and it is indeed one of the most powerful.
It also shows e.g. same (configuration) values close to each other for comparison.
windiff Directory1 Directory2
e.g. shows out of the box a list of different and non-different files in 2 directories).
If you click on any of that files, it will show the individual differences per file.
I did not find immediately commands to save all the differences between all pair
of file in a directory and its subdirectories (tried e.g. -D -T and -F command line parameter combinations).
Thanks,
I will incorporate it also in my TSE file difference program.
(After I received your tip, I decided to look again on Wikipedia (where your often find program 'Overview' pages), and searching for 'WinDiff', I found the overview page of file comparison programs.
http://en.wikipedia.org/wiki/Comparison_of_file_comparison_tools
)
Thanks,
with friendly greetings,
Knud van Eeden