Why use Ubuntu then? They have minimal commitment to KDE and there is the claim they neglect bugs or don't address them enough. Or can't. Furthermore, they cannot even have old hardware working properly especially since there is a constant issue whenever using effects (when effects are enabled). You'd be better off recommending Debian or Mepis if you are thinking of suggesting Linux to Windows users. I guess, Mint, too, as they at least polish 'Ubuntu' up but I am not sure how they handle or address the bugs.
I wanted to stick with an Ubuntu derivative if possible as this opens access to the widest range of pre-built packages, but, if I want to be able to ship a KDE desktop in future, it'll probably need to be a more polished distro than Kubuntu.
So I have to weigh the various pros and cons of Ubuntu, with its polish and Gnome desktop, or some other distro with a hopefully polished KDE desktop.
I've heard many good things about Mint, but until now have been too lasy to try it out, but that's about to change. It might just be what the doctor ordered.