Branches are usable only when a merge is not unnecessarily painful. SVN's lack of ability to track renames is a big pain especially in languages like Java where the filename corresponds to code itself. SVN is capable of leaving the codebase broken after a merge.

Here's an example scenario I described in my blog an year back. http://tuxychandru.blogspot.com/2010/01/how-git-shines-above...