I tried Atom when it came out, it was painfully slow...on a whim I tried it a couple of weeks ago to test the go-plus package for go development and, and I was pleasantly surprised how much performance improved, personally when both editors are open, I don't see a speed difference anymore. If you have not tried Atom recently, give it a go.
I still find it fairly slow but I'm going to try and use it as much as possible, anyway.
I like the core principle it's built on (completely hackable as everything is built on a scripting layer) which makes it more potentially powerful than Sublime, even if its slower now.
I seriously think Node.js is one of those things that get's overhyped. Yes it's fun to code...until the nested callbacks get's too much. For me personally I will stick production code with ruby/sinatra and eventmachine and play with node for personal projects.