This is a brilliant plugin for anyone who wants to pimp up their Joomla! e-mails from the standard, boring text to have a lovely, consistent HTML template.
The extension is extremely easy to manage, after installation it requires creating a template in a WYSYWIG editor with separate CSS editor and with a sample template already set up. Once your template is set up, just head over to your plugins and enable the Beautifier. That's all there is to it.
Certain extensions using their own templating system (JomSocial for instance) might require a little bit of extra work to be perfect with it but it's little price to pay for the benefits of a more professional look. Especially recommended for business users.