I like the ticket system and SVN integration.
The ticket system can be customized for intended workflows. It seems to work well with small to mid-sized organizations and is easy to set-up and maintain.
It's web-based, so you don't have to worry about backing up your work or the tickets. The integrated SVN repository is very nice, it's much easier to use than Hg Mercurial or Git and great for documents and Ranorex (automated testing). Review collected by and hosted on G2.com.