We tested git and hg at Loopt:<p>While both were faster than SVN (often <i>much</i> faster), they have huge disk footprints compared to an SVN working copy. In our case, the SVN working copy was ~1GB, and both the git and hg repositories were over 20GB. That matters when you have an 80GB SSD.<p>Also, since neither git nor hg let you check out a subset of the repository, we'd have been forced to break things up into lots of smaller, separate repositories, a prospect we dread.<p>Admittedly, we do some stuff that is questionable, like storing images and libraries, but we like keeping all the content the code uses and the code itself together.<p>For some newer, more isolated projects, like our mobile code bases (iPhone, Android, etc), we use git and love it.  But for our 4 year old server with over 100 projects, we couldn't realistically make the switch.