So, this school uses 100% open source software? I take it this particular school will not be producing any young graphical artists, filmmakers, or music producers, then?
For most tasks students complete on school computers, I would prefer to deploy Ubuntu Desktops instead of overhauled Windows XP workstations which need to be manually pampered into health. If everyone is using open office, all documents produced at the school will look god-awful, but this will be a grand equalizer between students, demonstrating to them that there is no place for presentation in academic content.
So, this will be fine for students in most subjects... but I have to feel bad for anyone with creative or artistic leanings. Linux is an engineer's world. While young programmers will be able "express themselves" with terrible unix code and tools, artists will be left learning with archaic and useless tools that have no bearing to professional software where they could be more productive on Macs or even Windows machines. They may not suffer from "vendor lock-in", but they will be subject to "industry lock-out". Ubuntu systems are really only pragmatic in some cases.
Every program is a part of some other program, and rarely fits.