I've been using Open Office since it was Sun Star Office. The other day I heard someone in a computer store telling a student not to use Open Office because "it's not compatible with Word." I hear things like this all the time - "don't use Linux because it's not compatible with Windows." The truth is that I can open any file on my linux computer. I do have XP and 7 because they are required for some classes I'm taking (and they are also free because I'm taking those classes), but I see no need for them. I was a teacher before I went back to school and I received papers in all types of formats, from OpenOffice, Page, Abi, Microsoft and even Han, a Korean language alternative to Word. Because I use Open Office I can open any of these files. Teachers who use Word have to tell their students to use a specific format because they can not read it otherwise. Changing formats seems simple to some, but it can be extremely confusing for people who are not good with computers. I was teaching English at the time so I didn't care if my students were able to change the format of their papers as long as they wrote their papers in English. I don't know why anyone would limit themselves to Microsoft Word (I also think AbiWord, is a waste of processing power) when there is a free alternative that is much more versatile.
-reply by Jeff