Putting action where the mouth is, I guess: At the very least with its 4.x release, I then and now considered the K Desktop Environment (KDE) to be the most technically advanced at least amongst the Open Source / Software Libre desktop systems. Took me a while to actually adopt it for day-to-day use. However, that time is now I guess.
opinion
Refactoring and removing.
Deleted code doesn’t contain bugs, they say. I always felt kind of unsafe with the idea of actually and straightforward removing code while into refactoring smaller or larger parts of the systems – after all, same as it doesn’t contain bugs, deleted code also doesn’t contain business logic anymore which might not be what you want at times. Yet, trying to clean up parts of (the Java / Java EE based) components in our system, I have to some degree changed my mind about that.