Although I use vi and Emacs roughly equally, I do recognize Emacs as The One True Editor, and so I spend much of my programming time booted into Emacs. And as I am now methodically replacing CVS with Subversion for my own needs, I cannot survive without the C-x v family of key sequences. Looking around for an Emacs VC backend for Subversion, I found two and decided to go with the one in the Emacs repository (Monnier) as it will ship with Emacs for the next release. Also, I was unable to find a canonical site for the other backend (Bowman) and when I byte-compiled the two, the Monnier compiled more cleanly than Bowman.
Time for the real test: work.
UPDATE: Well, one drawback to the Monnier version in the Emacs CVS repository: it only works with the CVS HEAD version of Emacs. Oops. For Emacs 21.4 (the current release), I need to use the Bowman version. But, it does not load ok. Live and learn.
And... there's yet a third version (Blandy) according to Karl Fogel. I'll give it a try also. Two things in its favor: it also compiles but and is the only one which loads ok, and it's the only version with useful setup for .emacs:
(add-to-list 'vc-handled-backends 'SVN)
(Magic, isn't it?) Easiest however probably is the most simple:
This seems the right one for now until Emacs 21.4 is out.