Both bzr and darcs are non-centralised. Branches are easy to make. I find that communicating patches in darcs is a little easier. I like darcs’ UI better than bzr’s, it has less commands, but doesn’t seem to miss any functionality.

The only down-side with darcs is that it isn’t “clever” in pushing, with that I mean that it requires a server on the receiving side, something bzr doesn’t. On the other hand that’s easily solved using sshfs.