Every year, most JuliaCon workshops are presented via Jupyter notebooks; the Julia support is pretty good and has remained stable for a long while.
Some of the unofficial extensions like `code_prettify` don't work for Julia kernels, but at least for my usage, I've never felt the need for such tools in a Jupyter notebook.
IJulia is falling behind. If you look at github activity, it has 1 commit in past month. Compared to 9 authors and 39 commits in past month for IPython. IJulia issues are piling up.
Some of the unofficial extensions like `code_prettify` don't work for Julia kernels, but at least for my usage, I've never felt the need for such tools in a Jupyter notebook.