Savannah accounts are project based and need approval.

I think the projects need approval and that we fall squarely in the category.

On github, anyone can
create an account, fork the chuck repository and publish his work in plain
sight.

That's exactly what I'm doing; http://git.savannah.gnu.org/cgit/fluxus.git/log/?h=redacted
I forked the Fluxus audio synth called Fluxa and added a lot of stuff to it.

I see that as a strong advantage as the community can experiment, leaving to
the main branch maintainers the possibility to merge interesting propositions
in a few simple commands.

I agree. But I still don't see why Github is better than Savannah for projects like ours as it sounds about the same.

Yours,
Kas.