The speed of branching in git, compared to subversion, was a huge part of convincing me to move. Not an entirely "fair" comparison given that subversion is a centralized VCS, but speed is very important.
This is the interface you're presented with, but it's actually a "cheap copy" underneath. So if you write "svn cp https://svn.myserver.com/trunkhttps://svn.myserver.com/branches/foo" that takes about 1-2 seconds in my experience (no matter how many files, how long the history, or how many binary files you have, etc.).
