As long as we're sharing anecdotes: I've seen Mercurial used very successfully with much, much larger repositories than Firefox and I'm fully aware that Firefox

As long as we're sharing anecdotes: I've seen Mercurial used very successfully with much, much larger repositories than Firefox and I'm fully aware that Firefox is already big. I don't know how big the full repositories were, but I am assuming at least several TB. I have never seen git getting pushed that far and I have no idea how it would behave then. My guess is that it would slow down a lot, but at least not fail entirely.