Just to give my own impression, I actually did a novel in Xy4 (at least most of it, I went back to Emacs to complete it). It went along pretty well but it was in English. When I started on a French language novel, there was a lot to set up and learn and I ended up back in Emacs to do all of it. I just this week set up Xy3 and I'll see what my impressions are over time. Initially I think Xy4 is easier to get started with, but ultimately I'm not a GUI/pull-down menu type, and likely the lean nature of Xy3 will prove pleasing. I'll report back in six months or so.