Used as a word processor, Open Office makes a startlingly good job of reading and writing MS Word documents. I have only found a couple of gotchas.
The old Star Office had a Basic language very similar to Microsoft's VBA. The new version 6, and Open Office, have kept the language and changed to an entirely new and largely impenetrable API. In other words, the syntax is the same, but the vocabulary has changed beyond recognition and no one from Sun / Open Office seems interested in helping people through the thickets of the new language, though there is a 2mb PDF manual available.
I have just discovered what looks like an excellent macro-writers' aid here. It is a macro, commented in German, which you should attach to a document. Select something in the document; run the macro: it will start a new Open Office spreadsheet in which all the properties and methods applicable to the thing you have selected will be listed.
The new API is so immensely frustrating that I have started a small collection of working macros, in the hope that they will be useful to others, who are encouraged to email me their own. I will post them here if they work.
Here are some to fill in obvious holes. Cut, paste, and enjoy.
Sub transpose
Sub CaseChanger
Sub QDWordCount