OpenOffice 2.0 or Word 2003 XSLT

I'm about to implement some kinda XML Editor for a customer schema. I was
thinking of using OpenOffice 2.x Import/Export Filters or Word 2003.

Has anyone ever tried to do something similar with any of those two? Which one
did you prefer and why?

I've seen so far that when using OO it's easy to code an import and an export
xslt and implement those through the filter options.
I haven't found something like that in Word2003 - so I would have to save the
file as a WordML and do the transformation outside of word, right?

Thanks for your input
jimmy