Hmm …

I once spent some time using git-svn to work with an ancient subversion server (for practical reasons - the git clone was much smaller on disk and `git commit` was about 15 minutes faster than `svn ci`).

That didn't last unfortunately; somehow it led to the svn server writing corrupt metadata to its own DB that it couldn't read, and I ended up spending a day to repair it by hand.

(Maybe this anecdote says more about the working conditions at that gig than SVN, but it was still an unpleasant bug to run into.)