For a long time now, I've preferred mark-up systems to WYSIWYG ones, and I think this is more than just a matter of taste.
The problem that I often see with presentation-oriented systems is that they encourage the user to concentrate on the presentation of the material rather than on the structure of it, and I think this reduces not only the accessibility of the content, but also the quality of what goes into it.
In particular, I like to see an explicit and complete representation of what a program is manipulating... to take a simple example, consider the white space between two paragraphs on a computer-processed page. Some people are happy to adjust the space as an amount of space... I prefer to work on it in the understanding of why there is that amount of space... how much of it is a pre-paragraph leader, how much is a post-paragraph trailer, whether any of it comes from headings, etc etc... I like to see the logical structure of a document or other file.
From the logical structure and content of the file, it should be possible to generate the appropriate presentation.
I particularly like line-by-line (greppable) ASCII data files, and Lisp... they have the great advantages of consistent representation of data in a form for which it's easy to write new programs for reading and writing the data.