I installed it on my blog as soon as I discovered it.
The community can decide where ClassicPress is going via a petition system. This is open source the way it should be. A stable and secure CMS with no surprises. I'm currently running about 20 sites on ClassicPress with no issues.
ClassicPress is the base code I learned from and worked with for 10 years and I'm glad to see it continue on without drastic (destructive) changes.
I used WordPress for 10 years before deciding to move to an alternative cms. My choice is ClassicPress. I do not like the direction WordPress is taking and feel very much at home in the ClassicPress community. ClassicPress stays true to the WordPress ideals and users on my sites didn't even notice the transition. It's exactly the same as the familiar versions of WordPress up to 4.9.9. It's also easy to migrate from WordPress 5.x.