I guess that's part of the disconnect between happy users and folks who find it too slow. Atom is an effective IDE for me. I have smart auto-completion, version-control integration, task runners, linting, and, for many of the languages I work with, definition lookup, a debugger, a repl, and inline reporting of compilation errors. It makes for a great markdown writer as well. As a daily one-off text editor I can understand the complaints. But compared to a proper IDE, the startup time is pretty competitive.