I’ve never used magit but my impression is that it’s similar to jj in the sense that it smooths out git’s rough edges in an elegant way and in the sense that it’s hard to properly appreciate without using it.

That being said, I also much prefer a UI layer (lazygit originally, now lazyjj), and personally I find the benefits of jj to be partly complementary to the UI ones.

That is, after getting used to jj, my problems with git are (1) the CLI ergonomics, and (2) the model is actually more complex than it needs to be, in a way that materially diminishes my experience. Only the first is addressed by lazygit (though maybe magit does both; not sure).

One other point: jj doesn’t actually impose a level-of-control tradeoff on the curation of commits. You can mimic the git workflow by modeling the working copy and staging area as commits (changes, in jj parlance), or you can experiment with any number of alternatives. What git gives you is the opinionated support for the working-copy-staging-area-commit approach.