If by that you mean windows: that's no longer the case. The git Windows installer is vastly superior to hg's windows experience currently. I'm using it daily and hg integrates really well into the system now. On top of that is tortoise git a very pleasant experience now.

I mainly mean Windows, but it is not the only non POSIX system around.

I am using Git on Windows on a current project and it is still far from what Mercurial was offering on my previous project in terms of usability and resilience to infrastructure issues.

> I am using Git on Windows on a current project and it is still far from what Mercurial was offering on my previous project in terms of usability and resilience to infrastructure issues.

Which part exactly? Git seamlessly integrates into Putty/PLink/Pageant and tortoise-git does the same. Git also has excellent support for end of line conversions. Mercurial last time I was checking required an extension to deal with line endings.

Git has had issues talking to the server, loosing credentials already stored, asks for the passwords multiple times, every now and then, a bunch of HTTP errors comes back when doing pulls/pushes.

The mercurial server is hosted on the same server and works without issues.