I feel that to be qualified to answer your question I need to have used a non-git VCS on a non-trivial project. Which I haven't.
That said, jujutsu is the one that's most sparked my interest and seems most akin to the subset of git features that I use in my daily workflow. (In the way that everyone apparently uses a different subset of C++, I imagine everyone uses a different subset of git.)
That said, I haven't kept experimenting with it cause I had to stay productive (same reason I still haven't switched to Colemak). But I still have the tab open. And I did eventually switch to i3. So, maybe one day.
I think fossil is not exactly post-git but runs in parallel with git. But definitely a good fit for small teams. For true post-git if you feel adventurous I would try jj or pijul.
That said, jujutsu is the one that's most sparked my interest and seems most akin to the subset of git features that I use in my daily workflow. (In the way that everyone apparently uses a different subset of C++, I imagine everyone uses a different subset of git.)
This blogpost was what made me try it: https://v5.chriskrycho.com/essays/jj-init/ which I found from this recent HN thread https://news.ycombinator.com/item?id=39232456. Other HN threads about it: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
That said, I haven't kept experimenting with it cause I had to stay productive (same reason I still haven't switched to Colemak). But I still have the tab open. And I did eventually switch to i3. So, maybe one day.