I would not recommend using Subversion on Dreamhost. I've been using it for a few weeks and have some unsolvable problems that really make it unusable.
I've spent enormous amounts of time on the SVN mailers working on the problems, and basically, it boils down to the fact that Dreamhost is using a very old release that has some bad bugs.
Personally, I don't think they should even offer it - unless they are able to provide updates to fix bugs it isn't really fair to the users. As was explained to me, they aren't going to try to update SVN on its own - they will just pick up updates as they get new Debian releases.
This is not good.