Mercurial seems okay, but I have an older version. Are the newer versions still okay? It would be worth having someone involved with Mercurial to make sure that modern scum don't ruin it.
I can think of at least one extension worth adding. This would be to replace my hosting solution with an extension. Hosting should be available to everyone, and then I wouldn't need to maintain my hosting solution.
Mercurial is written in Python, so this is for a Python programmer.