I'm not sunshowers, but I think the point isn't the exact number or a way of measuring it. For example, the reason I prefer to write Rust over C++ is not that I have measured it to be 2.6X faster for me to work with. My interpretation of what sunshowers was saying was more like "'technically better' can be enough, depending on much better it is, and I think Jujutsu is a big enough improvement [for me] that it's worth it".
For me, the important metric here is the intersection of two things: number of concepts, and power. I moved from svn to git relatively early in Git’s life; I started using GitHub in 2008. I’ve loved git for a long time.
jj has the ability to do everything git can, but has fewer primitives that are factored better. This means it is easier to use, while still retaining the ability to do anything.
I don’t know if that’s 10x, but it’s good enough for me that I’m never using git again.
I mean 10% and 10x metaphorically, the point being jj is much much much much better than Git. But I wouldn't be surprised if a dev can go from zero to being able to do complex history editing in jj, 10x faster than the same in Git.
10x is an arithmetic operation. Therefore, to make such an assumption, there has to be a quantity that operation can be applied to.
So, by what quantifieable metric is jj "10x better" than git?