We use Debian to power our file and groupware servers and our VPN server. Debian is very reliable and we only restart the four Debian servers twice a year after cleaning the hardware. We also have some Debian and Debian derivatives workstations.
Thanks to Debian we could optimize the cost of our infrastructure and recycle old units to run as powerful servers with nice storage capacities or second hand workstation. Our IT manager is a absolute fan of the Debian system.