1) you have to be aware that besides editing the plugin configuration you must also edit each user profile that you wish to have the button.
2) an odd arrangement of additional ACL must be configured inside the plug-in. (The odd part is that this is confusing and perhaps redundant).
But on the whole this adds a great efficiency and usability boost to Joomla editing. Fantastic!
However I will say that the support forum is good so eventually I got things figured out.
Only minor issues were found. When authoring a document you don't know you have this feature until you start to save the article. But once you use it you are impressed. Also it needs a small hack for the spelling of begginning (sic).
But when you use it you really get that Eureka feeling! Well done Paul.