I did some more tests on AjaxWrite. My previous tests here. It's better than it was, but save still does not appear to be working completely. The Word header / footers appear to be stripped out. But, at least I was able to enter text, save it locally, and then open the doc locally and see my text. It still seems sporadic, though.

Beyond that; there have been a few more Ajax style apps released.

I haven't tried anything beyond Ajaxwrite, so can't speak on the good or bad of any of these other sites.