> Adopting CodeMirror pushed us to write more in a more functional style that makes the code more fun and simple (not easy) in the shortrun, and more maintainable in the long run!

I had a similar kind of good experience with code-mirror. I was writing my first proper compiler, and making a total dogs dinner of it. As a distraction, I decided to try put together an editor with syntax highlighting with CodeMirror. In the process of just fitting my compiler to the CodeMirror recursive descent parser I ended up bringing my compiler back from the brink of disaster. It feels really nice when a framework/API has enough good-taste/-engineering built into it that it improves code that uses it :)

I'll be interested in seeing how the upgrade to 6 goes - I'll wait until it's officially released, though...

(People've been using said compiler + IDE for about ten years now)