Dunno if it helps much, but that's what I do:
I use latest Wordworth that has a nice support for tables (ver 7) and export it in rtf format. MS Word reads it without trouble. The other way around works fine as well - Save as RTF from Word and Wordworth will open it. Only thing is, and that has nothing to do with formats or word processors, you have to have the fonts installed in both systems (via t1 or tt managers on miggy) to have the docs displayed properly.
Also, you could try Word 6 on Shapeshifter. On 030@50/AGA it worked just fine, albeit kinda slow, on 040 or 060 + RTG it's very fast and it will open native Word docs, even ones created with Office 2003 (haven't tried 2007) with a little need of reformatting.
Also, on aminet, you can find word converters for text, but, obviously, nothing advanced will be preserved.
AmigaWriter 2 seems like a good alternative, but I haven't tried it and dunno how compatible it is with actual word docs and at what degree it preserves advanced formatting. I don't even know if it has tables.
