Are the tools like Monticello adapted to GIT? I don’t think so.
And by listening the ones that already moved to GIT, it seems very complex.

So without a great interface that abstracts all the complex details of GIT, I am not in favor of moving to GIT.
There certainly are big issues like a LOT of crashing on Windows, and it does feel a bit worse experience compared to native git, but at least for me personally (on linux) I am much happier with it than with SmalltalkHub; doing large-ish merge conflicts is so much more convenient.

But I kind of thought that Moose was fine with their setup (considering they've done great things with it), so I am curious what are their (main) motivations to move to GIT.

Peter