The Page Builder CK editor is actually not an 'editor' because you don't install it as a default editor, and it is MUCH more than what we've been used to in a Joomla editor. This is exactly what it's name says - a PAGE BUILDER.
By adding this to your Joomla! site you can now build very complex page layouts without needing to know what divs and css are.
Of course you DO need to know what good design is. No extension can compensate for not having design skills. It will definitely allow you to make some very ugly pages (just look at our demo page we create in the review video). But those ugly pages are much more complex than you could ever have done so easily before.
Also, this is an 'article - page layout' tool. What you create still must fit within the bounds of a Joomla article area of the page (it does NOT allow you to create Joomla page templates). Although, the extension does allow you to create these 'pages' in many different locations - aritlces, modules, other components - basically wherever you have access to a 'editor' entry area.
The base system is free but the additional package called "Page Builder CK Params" gives you additional block types as well as a number of very useful features (like saving and re-using page layouts).
This is definitely one of the top extensions to install on your site (AFTER you have it fully secure).