Hmm, for encouraging development (assuming that learning the revision
control system was a minor cost, which I think it is not here), then in
principle it would be better to have many independent fronts of
development as in git or Mercurial than a centralized system.
For example, looking at the Linux kernel git repository
(http://git.linux.org, there's a sense of ownership that seems good to
encourage. On the other hand, if converting over to svn is easy on
savannah, that's a good solid improvement.