I've been test driving Atom.js and I like it pretty well. Something I don't like about it, is that the startup welcome guide keeps coming back. After several days of using it, I finally noticed how to turn it off.

In the left hand pane, at the bottom of the text there is a checkbox that disables the Welcome Guide. I think it's pretty hard to see, at least with the dark theme, but just uncheck it and you are good to go.