If you want to maintain an existing site built with some other tool, or want a straight HTML editor, forget it. SiteSpinner is not for you.
If however, you want to substantially revamp an existing site, or you want start a new site from scratch, SiteSpinner is it. You don't need to understand HTML -- but you do need to understand drag-and-drop. ;-)
To help you design your own web site, the latest versions provide some nice-looking templates. There are excellent tutorials, sample projects, and user forums. There is a spell-checker in the text editor, which I like and need. There are extensive capabilities to create and manipulate images. Popups too. If you want to do extra-fancy stuff, you can easily include external code, or things like flash animations.