I use markdown extensively on my website and so I tend to keep an eye out for new developments and editors.
Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML).
Whilst beautifully simple initial implementation as it has grown in popularity it has evolved and with no unambiguous specification has become fragmented, however I’m delighted to hear that there is now a standard markdown specification in development. There is more information on the website http://standardmarkdown.com.