I’ve been adopting jj for my personal projects for 1-2 months and have been very happy with it. One downside is if you move back to edit older revisions, it’s very easy to accidentally append something that was added to .gitignore in the meantime. I suppose it’s a relatively unique problem. Other than that I definitely like it, but my git knowledge accumulated over the years is still much larger than jj.
I’m going to be slowly adopting it for work.