Could you (or someone else) possibly expand on that? Is writing in raw HTML generally discouraged? I am totally ignorant in this area, but I am curious about it since I admire Mark's formatting and he seems to get a lot done.
But I certainly wouldn't want to write an entire book in HTML - it forces you to type a lot of brackets and tags. I'm sure your editor could take a lot of work off your shoulders, but even at that you end up typing a ton of macros (I would think). In any case, it seems easier to me to type the bulk of it in Markdown (or the like) and only occasionally drop down to raw HTML. To each, his or her own though.