I'm afraid my sarcastic description of window versions applies to Bazaar-NG.
http://bazaar-vcs.org/BzrOnPureWindows says: Failing tests in bzr 0.6 selftest is failed for some tests. Mostly because some tests written in non-windows compatible way.
The current version is 0.7: failing tests can be a temporary problem, but not updating the results clearly shows neglect. Now I've found the Windows installer, but the first choice seems to be Cygwin. Can you explain the shortcomings of Mercurial, apart from developer attitude and lack of renaming support, and the specific Windows problems it has? You make very generic statements.