Well Emacs is faster to me because its just a lisp interpreter written in C, tightly close to the hardware. So yes, Emacs is like 80% Elisp, but it still runs fast, and its stable. Editors like Atom are a bit too... "abstract" maybe. If I understand, Atom is CoffeeScript/JS running on a the Electron shell which runs on NodeJS which is written in C++ IIRC. Thats at least 3 levels of abstraction in my point of view, and knowing that Electron is Chrome based, it can't improve its speed. Simpler is faster