Changeset-based "distributed" version control systems (like my favorite, darcs) make patch management and integration possible in a way I haven't seen in subversion, and I see patch management as central to defining the trunk of a project. Say you want to merge the changes I've made over the past three days, because I just made my branch of SQLObject self-aware. (Bouyeah.) With a tree-based VCS you must calculate a diff between my tree three days ago and my tree now and apply that patch to your tree. With a changeset-based VCS, you just apply my patches. Svn's merging is rudimentary at best for this reason. I make mistakes with it all the time in my repositories - and I'm the only committer!
About hooks, I see svn like a car that you can put a different spoiler on, but darcs like an engine you can hook up to a different transmission if you like, and put in a car of your choice. I can see my way much more clearly to building more complex and wonderful things with darcs than i can with svn (e.g., making some sort of dynamic branch-maker-and-authorizer with apache and python and sane security and permissions and discussion, that deletes old stale branches and doesn't take too much space).