But does it do OpenDocument and Impress files correctly? I see this a lot, people don't actually want Word Processing software, what they actually want is Word Document Processing software. So the native well supported formats are ignored in favour of the defacto standard.
It's not surprising, but if you want to do the switch you really have to go the whole hog. You can accept Word documents with caveats but have to make clear that your supported format is OpenDocument and encourage it's use. You could easy provide links to the implementations and say they're obtainable for free, much like we used to link to Adobe Acrobat when PDF documents were first used.
I see office documents as a barrier to progress. People will throw a form in word or excel format to their users, both of which have atrociousness usability, rather than putting up a clean and simple web form. It's a symptom of laziness and the whole "I'm really familiar with this so I use it for everything syndrome". It is nice in a way though, the ability to edit documents you have to sign or add new clauses can be advantageous :-)
I use OpenOffice for Word Processing (but Gnumeric for Spreadsheets) but if I'm going to share documents I'll normally do it in PDF. If a preferred format is specified i.e. Word or RTF, I'll generally send the OpenOffice file as well, but I don't like sending editable documents unless they're likely to be edited.