A lot of these arguments seem to stem about whether git or hg is better, which seems about as useful as arguing vim/emacs or Windows/Linux/OS X -- it depends on

A lot of these arguments seem to stem about whether git or hg is better, which seems about as useful as arguing vim/emacs or Windows/Linux/OS X -- it depends on what you need and what you already know. If you're okay with using closed-source services, Fog Creek's Kiln allows you to have repositories that can be accessed with both git and hg; commits/branches/bookmarks in one will show up in the other automatically. It seems to me that this argument could be solved if someone went and built a F/OSS equivalent that did the same thing for the emacs devs.