I’m a (more or less) happy KDE user, ever since the KDE 3 days. Before that, I used fvwm2 for a long time, but that is a different story. It also happens that I never really reinstalled my home directory - the oldest files I can find are from 1997, and that is pretty much when I switched from an old Slackware system with self-compiled updates, to something with a more modern distribution. That means, that all the time from 1997 to today, I carry the same
/home/ads across my computers. The home directory grew from a few MB to 133 GB today (maybe I should clean it up, but then again it’s cheaper to buy a bigger harddisk).
It also means, that I never deleted my KDE config, even when upgrading to KDE 4 or Plasma.