The only real benefits I saw in distributed systems were private
branching and offline work. The former seems like it could be achieved
in Subversion by creating semi-private user directories like FreeBSD
does. As for the latter, while it's sometimes unavoidable (e.g. working
on an airplane) isn't something we really want to encourage.
First of all, I think most of the version control systems had progressed
to the point where virtually anything was an improvement over CVS. So I
was glad to see FreeBSD make the jump and convert to subversion. It's a
good system. So I have no axe to grind there.
The only thing really lacking is a good way to handle local code. The
old method of using CVS_LOCAL_BRANCH_NUM is very fragile. How is
everyone managing their local code now with the conversion to
subversion? This is the only place I miss using hg or bzr.