Recs.
Updated
This is an open source CMS that uses Markdown. There are options for visual customization and an active community.
Specs
Pros
Pro Easy backup / restore
The whole customizations live in one directory and as the system is file based, it can be easily backed up. The best way to backup is to use the backup function in the backend. It will create one ZIP file containing all your customizations. Restoring is then as simple as extracting the ZIP file.
Pro Very easy to create forms for the editing in the admin backend
It is very easy to create specialized forms for adding content in the backend. This way you can easily adjust the system to your special needs. Just an example: You need a site with events, then you can easily create a form where you can place e.g. date and time fields to be entered comfortably.
Pro Good documentation
There exists a very good documentation site touching on every point of the CMS. From MarkDown to themes, from content generation to image formatting.
Cons
Con Some plugins outdated / badly documented
There are some of the plugins that can break your neck. E.g. the LDAP-plugin (to attach the login to e.g. an Active Directory) has been created by the Grav team for some customer. But it is obviously so much customized, that it cannot easily be applied to different configurations. Also the documentation for the plugin is very bad. It resulted in completely breaking the site, not being able to login to the site anymore. Thanks God there is a very easy backup / restore function included. Use it!
Con You cannot easily switch theme
While you can easily install the theme, it doesn't automatically switch the whole site to e.g. different colors. Or if you buy a theme from one of their contributors, you can easily install it. But then the work starts with creating the site structure, where you place which widget etc. It's not that you switch the theme and get your site in a completely different look and feel. Certain conditions must apply, e.g. you have template files for all the needed widgets or parts of your site.