About 10 seconds of startup opening a directory, from terminal to loaded workspace. I'm on a MacBook Pro (Retina, 13-inch, Early 2015). I have 76 community plugins installed.
I have too many. But it works well for me. I've worked on too many languages with the same editor, so I've got... Front and back-end JS tools (linting, tern autocompletion, builds); clojure with a repl and parinfer, paredit; some rust and elm plugins that can probably go since I just experimented with those mainly. Linter for terraform. I also use atom for general note taking, so I've got a couple plugins for that.