The last time I looked at darcs -- which, admittedly, was years ago -- there was a problem where, under certain poorly understood circumstances that tended to apply to most people with large repositories, performance would fall off a cliff, meaning IIRC that from then on, every merge could take hours. Or years -- I think it went exponential.
The Wikipedia page about darcs says "Although the issue was not completely corrected in Darcs 2, exponential merges have been minimized."
I wonder what "minimized" means here. On the face of it, this seems like a pretty compelling reason not to use darcs for anything important.
I haven't experienced that issue in years. I do remember the issues it had before, and thankfully they seem to have been addressed. I don't know how up to date the Wikipedia entry is, but to the best of my knowledge this issue has been resolved, especially if you use darcs2 formatted repos.
The Wikipedia page about darcs says "Although the issue was not completely corrected in Darcs 2, exponential merges have been minimized."
I wonder what "minimized" means here. On the face of it, this seems like a pretty compelling reason not to use darcs for anything important.