@Izzy in Vancouver Drupal Users Group drupal slack channel posted one of the best testimonies I heard about #Backrdrop CMS:
Backdrop CMS isn't a retro project! I've been testing out Backdrop CMS recently and from what I've seen it isn't a Drupal 7 preservation project. Backdrop is a future ready development of Drupal 7. It preserves the values of low barrier to entry and building on what you've done before. It includes many advances including it's layout system and fixes and techniques in Drupal 8/9/10 without composer, symphony etc. The maintainers of core and contrib modules are amazing and keep tabs on what drupal is doing and I'm sure some of them are also working with drupal. In many ways it is the best of Wordpress and Drupal. Content creators coming from Wordpress will be comfortable with the way Backdrop uses layouts and blocks and site builders will love the super powers of Drupal with entities, fields, views, etc. There are a lot of modules and more being introduced every week. There is a very active chat that is publicly accessible if you just want to browse. https://backdrop.zulipchat.com