It looks like another good content editor has entered the WYSIWYG ring: Trix. Created by the Basecamp team, it supports all common document formatting, is clean and easy to use and facilities embedded attachments.
Even more exciting, Trix outputs clean and solid HTML that isn't munged when editing content after it has been created. Anyone who has developed a user facing application, that requires extensive content editing, can appreciate the need for clean and concise generated HTML.
My default editor choice is almost always wysihtml5 but it has a few quirks depending on what functionality you need. I will be giving Trix a closer look soon!