Have you tried creating a .sxw file (an OOo document) and then unZipping it to see its component XML parts? I'm amazed at how transparent it all is. What could be the reasoning behind MS Office's move away from XML formatting (other than to retain its proprietary nature and thus continue to charge ridiculous sums for its wares)? XML is the logical way to store and retrieve information regardless of platform.
I've also fooled around with changing MSWord files into OOo files and they look and act EXACTLY the same, keeping all of the formatting, &c. However, the OOo files are almost one THIRD