I just downloaded this editor, but I need exactly a lot of functionality. I have several of them, but today at the seminar the question arose as to which of them is the most convenient to use. It turned out that the most sophisticated of them is Emacx, but also difficult to learn. I will try to figure it out and then work comfortably. By the way, my decision was influenced by the news that V. I. Arnold himself worked on it.