My chief complaint is that it's built on "patch theory", which is ill-defined and doesn't seem particularly useful. The Bazaar/Git/Mercurial DAG model is much easier to understand and work with. Possibly as a consequence of its shaky foundation, Darcs is much slower than the competition -- this becomes noticeable for even very small repositories, when doing a lot of branching and merging. I think it's been kept alive in the Haskell community out of pure "eat our dogfood" instinct; IMO if having a VCS written in Haskell is important, it would be better to just write a new implementation of an existing tool. Of course, nobody cares that much about what language their VCS is written in, generally. Beyond that, the feeling I get of the three major DVCS alternatives is: git: Used by Linux kernel hackers, and Rails plugin developers who think they're more important than Linux kernel hackers hg/bzr: Used by people who don't like git's UI, and flipped heads/tails when picking a DVCS (hg and bzr are basically equivalent)