YMMV, obviously, but I find it extra work to post at DW personally because of the header info. I used to post in both places but eventually stopped doing it at DW because of needing to write out and hand-code the headers, links, etc - with AO3 it's just a matter of ticking boxes and pasting in the text. (I don't usually do anything complicated with the HTML, so I've rarely had to fight with it too much.) I mean, it's kind of like ... yes, it's not that much extra work. But it *is* extra work, and some days for me handcoding all the formatting/link tags on the header is just that little extra thing I don't want to do.