I have not tried OO for HTML lately, but my experience is that it is still sub standard for me, and OO changes things I do not want changed when I have input it directly as source and go back to WYSIWYG editing. Not, nice. To much of a hassle.
I don't use OO on a regular basis, but what I remember is that I had to go back a clean things up in the html a little bit -- but *nothing* like winword which just absolutely shreds everything... ..Just playing with OO now again, what I find is that OO "whacks" my style definitions, and renames my classes to derived class names of its own. But other than that it doesn't seem to introduce problems of its own. and these class/style problems can be fixed in a few minutes using any regex text editor. The way I get OO to "work" is to create via File/New/HTML Document a new HTML document in OO, go into View/HTML source mode, paste in my previous HTML work (if any) click View/HTML again to put it back into WYSIWYG mode (it requires a file save on the new HTML document) I can then edit in WYSIWYG mode without it munging stuff other than my style/class defintions, which can be fixed in the end using a std regex text editor. Now, I don't feel compelled to work in WYSIWYG mode -- but its there in OO for people who want it or feel that they need it.