Artof Editor is a WYSIWYG plugin for Joomla based on the very popular CKEditor. It is up to date with version 3.6 of CKEditor.
This plugin gives you the ability to select a different editing toolbar for frontend and backend users and several other features. This is a simple editor but my personal favourite to use with Joomla, particularly if you are writing technical articles with code snippets, and does not suffer from some of the feature bloat compared to other editors (like JCE). It's simple, it works and it's free.