I've run the gamut of Linux distributions, from the incredibly simple to the overly complex, from modern interfaces to old-school throwbacks. I've used Fvwm95, CDE, KDE, Xfce, AfterStep, Blackbox, ...
Mabox is a free, open-source operating system that is available to download and install on as many machines as you need. This user-friendly desktop operating system is beautiful, fast, and reliable.