BlueGriffon is an interesting WYSIWYG editor that uses the Mozilla/Gecko rendering engine, and is worthy of note not just because it is usable (albeit with a few UI niggles) on a Mac but also because it includes a simple (but quite usable) SVG editor.

The only significant downside is that they’re trying to monetize add-ons for almost trivial tasks, so it makes you wonder how far that will go.