Physics and Astronomy runs Debian on the main departmental server. There are workstations and servers throughout the department that run on Debian which are used by faculty, staff and grad students. In the science theaters, a lab of twenty+ Debian workstations is open for all physics students to use with a central Debian lab server.
We find Debian as reliable and as easy to use than the previous SGI Irix machines and the Sun Sparc machines. Some of the Sparc's have been converted to Debian OS. We still do computational work with SGI and Sun's but hope in the future to have a Debian cluster up and running (funding permitting).