Why Kiln is based on Mercurial, and not other (D)VCS

Question

What were the reason for chosing Mercurial as a basis of FogCreek Kiln, a source control management system with tightly integrated code review, and FogBugz integration?

Answer 1

I think the issue of hg vs. git is a red herring, as the OS support issue alone is a major difference. The real question is why hg rather than bzr, as these two are very similar and hg developers themselves consider bzr to be their real competition and vice-versa. Sun conducted an extensive evaluation of both when it came to choosing a DVCS for OpenSolaris and OpenJDK. One would like to know what was the process used for picking hg at FogCreek. All we got so far by way of answers (apart from the OS support issue) are generalities.