I use HTML for my documents (when plain text won't do) and so I needed a good HTML editor. I used Mozilla Composer for a while but it sucked big time. There doesn't seem to be an easy way to move rows within a table; drag and drop creates a nested table. (How stupid!) And what is extremely irritating is that you can't right-click a file and open with Composer. Moreover, the look-and-feel made me slightly uncomfortable. So I tried Frontpage 2003. I was wary because previous versions of Microsoft apps generated horrid HTML. But I found to my surprise that Frontpage generated clean, simple HTML. (Surprisingly, Frontpage by default cleans by Word's bloated HTML.) And the user experience was a million times better.
All this reinforces the view that open-source software, by and large, has terrible usability. Also, Microsoft's apps are better than they get credit for - sometimes far better.