All this hg vs git, but no one remembers monotone (which had some influence on git's development)
www.monotone.ca
Its a single file binary
Its supported on windows, linux, solaris and mac
has an interface for both scripts and users
Great documentation (and an easy to follow tutorial)
Interface is Stable
Single file to store the repo. I enjoy this b/c it makes backups extremely easy.
Negatives are:
It may not be as fast as Git, but the difference is barely noticeable.
Pulling an initial repo from the master is slow when there are tens of thousands of commits in the tree. After the initial pull, sync's between repos are quick.
Diffs in MS Windows takes substantially longer than in linux.
Monotone may not be a perfect choice for the linux kernel, but its a great DVS that's easy to use, stable and lets linux/mac/windows guys work together.