I have been using sublime for quite a while now, it suits my requirements. Like you said it's highly customizable for e.g. I use a package that enables React.js syntax. I also tried using Atom, couple of months ago, but I found it to be slow maybe they have improved it now.
I have seen lot of people using Webstorm IDE as well. Its a good choice if you are a JS developer and need the support that a text editor doesn't provide.