I've used Eclipse for PHP/CSS/JavaScript for too many years, it is still the only Open Source IDE than can do auto-completion, outline and Go to definition, Go to reference reliably for PHP.

But things have gotten to boiling point. It can't handle newer technologies, like LESS, there is no good extensions for anything relatively new.

I think Atom (and my preferred VS Code) is the future of IDEs, there is a lot of people behind these working on new features and extensions for these. And having HTML rendering engine behind the IDE does make it more approachable for hacks, simple and useful ones.