After comparing between Ubuntu 12.10 and 12.04.1, where the verdict was mixed, next in line is Kubuntu. Like Gnome 3 shell, even KDE is going through a lot of transformation and users are bearing brunt of it. KDE 4.8.5 actually made me prefer XFCE as my primary desktop. However, KDE 4.9.2, I heard, has fixed a lot of the previous bugs and instability. KDE as a desktop is, possibly, the closest