Actually, there is also Rapid CSS 2008, and all three of them are basically the same program which is a pretty good editor with a mock MS Office 2003 Interface and some decent features to help you with your code, along with a real time preview (like Dreamweaver – but you can’t edit in the preview window)

So it’s not a WYSIWYG tool, but instead a handy tool for people that know how to code and want to do it faster, or people that want to learn and can benefit from pop-up/drop-down menus of code completion and features like HTML Tidy and FTP.
It’s like the free (and dated) HTML-Kit, but with a visually better interface. Also in the Webuilder, there is support for more languages, like Ruby.
Notepad++ has been a great little tool for all coding needs, but this might appeal to people who want a little bit more of a MS Office interface and a little bit more hand holding.