Wordpress is the leading CMS since many years. About 30% of all sites around the Web are made with Wordpress. That's great. It's incredible how a single product can be that used so much around the world.
Ghost is a crowdfunded CMS using NodeJS. The main objective of John O'Nolan, the Ghost initiator, was to make an open source blogging platform which makes writing pleasurable and publishing simple. And I think that the goal is totally reached.
The main reason why I installed Ghost, except the great interface, it the markdown editor. It's just awesome. Instead of basing the CMS around a WYSIWYG editor they choose to implement a markdown editor. The main advantage is that the end-user can focus on writing and not on the layout.
The second reason why I chose Ghost for my blog, is that I wanted to try something new. Since I have been interested in development, the "default" blogging platform is Wordpress. It's cool that a challenger like Ghost exists.