I install Kubuntu for newcomers to Linux
I have to say that I've never spent more than half an hour playing with Unity. I was convinced pretty quickly that it wasn't right for me. I switched from Gnome to KDE at that time.
Since then, I've introduced several newcomers to Linux, who came from Windows. For them, I also installed Kubuntu, because the menus, out of the box, work in a way that a Windows user might expect and it should be possible for them to learn to find their own way around.
I did the same for my wife last week and haven't needed to show her anything yet and she's the kind who can't create message filters in Thunderbird, etc, but no problems with KDE.
I think overall I'm happy with Ubuntu, so long as nothing comes between it and KDE. I like the stability, I like the fact that most software distributors provide software compiled for it, I'm happy with the vast amount of free and easily installed software in the software center.
If I were to move to Fedora, for instance, I would lose those benefits. It's beginning to sound though, as if Mark doesn't want KDE users. We'll see.