Mercurial seems to be a "nicer" version of git, which doesn't seem to be enough of a difference to avoid the git bandwagon.

Projects like pijul interest me, since they work in a fundamentally different way. Pijul is a "nicer" version of darcs. Git killed darcs not by being nicer but by being faster, and pijul is also faster than darcs, so maybe there's hope ;)

(Of course, most of git's momentum came from huge projects using it, like Linux and Xorg; yet being huge is precisely what forced those projects to favour speed at the cost of "niceness". If a "nice" system existed that was fast enough to handle Linux, Torvalds would probably never have written git).