KDE 4 is now mature and better than KDE 3 ever was. On recent Phoronix tests
on Ubuntu, KDE was faster than GNOME 2, 3 or Unity for most things. I admit
that it was a performance dog when first versions were compared to KDE 3,
but that has not been the case for some time. Now the performance dogs are
Unity and GNOME 3. But I admit that that too will change. Any new desktop
environment has wrinkles to iron out. That was the case with KDE and it is
the case with Unity and GNOME 3.