DesktopBSD is a custom FreeBSD-based desktop focussed on stability, usability and simplicity. In developing an easy to use desktop operating system, DesktopBSD has chosen to use KDE. Screenshots showing the desktop tools in action are available.
Their website FAQ further explains the choice of KDE:
"KDE is easy to work with and has many useful features and well-integrated components such as the PIM package (Personal Information Manager). Additionally, KDE is probably easier for people that used Windows before, but this is rather a nice side-effect than a main reason for this choice."
"Of course, there are other great desktop environments out there that are in some ways superior to KDE, but we decided to use only KDE so we can have better support for that one and have better integration of the DesktopBSD Tools with that environment."