I don't know what you mean by ergonomics, but I remember trying both Mercurial and Git back in the days after using Subversion before. I didn't like how Mercurial didn't easily let me rewrite history and do stuff like `git commit --ammend` or `git rebase`. Mercurial users kept telling me using an extension to manage patches on top of Mercurial (I think it was quilt).
I agree about the Windows support. hg serve was also nice. Plus TortoiseHg.
Mercurial does let you amend commits like git does, histedit is essentially identical to rebase -i, and evolve is better than anything git has.