Should I be using SVN rather than Darcs or Git?

Subversion has apparently become the version control system of choice
for Ruby developers --especially now that Ruby itself uses it. I
suspect that might have a lot to do with Rails and Rubyforge. Ruby
only switched over to SVN well after Rails had been using it. And
Rubyforge currently only supports SVN and CVS, which I find a bit
surprising since, from what I understand, supporting Darcs is just a
matter of having Darcs installed. And I can't imagine Git is much
different.

So I'm wondering, what's so special about SVN as opposed to the other
choices? Is it because SVN is more like CVS than the other choices?
The fact that SVN isn't distributed I would think would work against
it (though I hear SVK is supposed to deal with that). Darcs is written
in Haskell, and from the word on the street a lot of Ruby folk seem to
like Haskell. Also, Git was written by Linus Torvalds, which is about
as good as credentials can get.

Thanks,
T.