I think Torvalds also goes on that list as another ACME user. He mentioned as much in the extended video interview he did with Microsoft recently.

For myself, I've had to spend a lot of time without colorful syntax recently as I was working on building my own IDE and my own syntaxes and even my own system of syntax highlighting. It would have been a distraction to be constantly fighting with someone else's system of syntax highlighting while building my own! But also even having learned that I can live without it I'm hardly ready to say that I never want it back. I just want it back better. I want dynamic, contextual highlighting and I want interactive access to the underlying tree model. I want it to feel really easy to tinker with too.