Statamic is a CMS that admittedly we don't use for the bulk of our website builds but it has undergone some big changes recently that we have been paying attention to. A lot of the features that we enjoy using in Craft CMS have now made their way into Statamic and it has also seen improved compatibility with laravel projects.
Laravel is a PHP framework which is used to code applications. This framework now has the option to quickly add Statamic to an existing application to enable it to use the CMS.
Statamic uses a flat file system called yaml instead of a database. This means that is is very lightweight and fast but more suited to smaller scale sites. This is because a file is created for each entry, whereas in a typical database these files would be represented by rows within a table. As a result of this, yaml is very fast at reading data as the file only contains what it needs and there are no connection details to be processed, but the drawback of this is that having a file for each record can get out of hand and potentially take up a lot of space on your hosting environment.
Statamic has come a long way since we first started using it and we still keep an eye on it's latest features. We occassionally use it for the odd project and it works very well for small sites where a CMS such as Craft or ExpressionEngine would be overcomplicating matters.