Backdrop CMS is the Drupal fork. Based on the familiar APIs of Drupal 7, Backdrop provides a more compatible and more affordable alternative for upgrading existing Drupal sites.
Backdrop CMS is a faster and less-complex version of Drupal 7 with Panels, Views, and Configuration Management in core.
But Backdrop CMS is already at version 1.4. Lots of new core features have been added since it's release: a built-in Rich-Text editor, built-in auto URL aliasing and page redirects, and a project browser for adding new modules, themes, and layouts directly from your site. Backdrop includes an updated administrative theme, dozens of UX improvements, and improved APIs for developers too!
At the same time, Backdrop CMS always provides an upgrade path (via update.php) and maintains a high amount of compatibility between versions (and between Drupal 7 and Backdrop CMS). Decreasing the amount of time spent on development, both to in building the site and in maintaining it, should help bring down the cost of long-term website ownership.
Hundreds of sites are now running on Backdrop CMS. Come and see if it's a match for your next project!