Can't comment on Mercurial, but "for all my personal project where I don't need to care what anyone else thinks" I am using Fossil. Ever since that decision, I've felt a bit, well, held back, or rather, I don't feel quite as comfortable as I do at home when I have to use Git.
I've always been interested in Fossil, especially how they handle all the things in a project that aren't strictly code but still need to be tracked.