During the transition from JRoller to Blogger one of the factors that drove my decision were the available editors. Both offer some sort of WYSIWYG HTML editors to compose blog posts. However I was not too pleased with either one of them. Both tended to produce somewhat bloated markup with lots of divs and spans, combined with inline style attributes - in the end not really much better than <font> tags...
In the end I gave up on the "rich edit" modes and wrote the markup by hand, usually with Bluefish.
While I was generally fine with that I still kept looking for some decent blogging tool a little more sophisticated than either the browser's text-area control or Bluefish. I tried ScribeFire for a very short time, but was not pleased with it. Maybe it suits people better who usually blog about stuff they find while surfing the web, but for me it just did not work. Finally - I cannot really remember when or how I got to it - I stumbled across the Windows Live Writer.
It has a lot of nice features, one of them being the ability to download the layout from your actual blog (BTW I just tried this with my Blogger account, even though there are other types supported and I just assume they offer the same functionality). This allows you to write stuff with a very close approximation of what the final posting will look like.
You also get a "preview" mode in which you can see the full page layout complete with graphics and style-sheets. This is really nice to get a final look before publishing, because frankly the preview mode you get in Blogger's web interface plain sucks. JRoller at some point upgraded to a newer version of the Roller engine apparently and got that better from then on.
And apart from the plain GUI niceties, the HTML code that gets generated is really nice and clean. You may even choose between standard HTML mode (in which e. g. <p> tags are not closed) or XHTML compliant code (which I prefer).
Images you want to insert are automatically uploaded, so no hassle there, either. And you can put borders around it in different styles as well:
The one thing I missed though was the ability to insert custom snippets of HTML code, e. g. a <pre> tag with a specific class attribute. To do I had to switch from "rich editing" to the HTML mode and insert that manually. Today I found a nice template plugin (did I mention there is a plugin-architecture? ;-)) that allows me to do just that. It can do even more, because you can include snippets of C# code inside the templates. E. g. the following code was first written, then selected and finally the template with that code in it applied.
<%= _selection %>
I have come to like this tool so much that even when working on Ubuntu (which is most of the time) I fire up a VirtualBox'ed instance of it.
So in case you have not found your favorite editor yet, are always ready for something new and - that one might be a show-stopper ;-) - you are not completely anti-Microsoft, go have a look and try for yourself.