Python goes Mercurial
Python is moving to a distributed version control system (DVCS), but unlike many projects which have moved to Git, Guido van Rossum has selected Mercurial, also known as Hg (the chemical symbol for mercury), as the DVCS for Python.
van Rossum says it is "hard to explain my reasons" and that it is "mostly a matter of feelings". He feels it's better to decide now than ponder the issue for another year. According to the announcement, Git was eliminated because, "while it has obviously many fans, it also provokes strong antipathies".
The options were then Mercurial and Bazaar (Bzr) which are both implemented in Python. An unscientific poll of feedback in van Rossum's email in-box and "on Twitter" gave him the impression that support for Bzr was limited beyond Canonical employees and Hg had a strong following. Coupled with his belief that Hg was easier to learn for Subversion users and a feeling from experiments that Hg was faster, van Rossum selected Mercurial.