"As mentioned, KDE 4.2 is frozen, so the programmers are focused
on bug fixes only. Frankly, I can't feel any difference between
this and the previous version. One annoying thing is that KWin can
stall while working, and then I get informed that the effects were
working too slow and have been suspended. I don't know if this is
still the NVidia drivers or the Window Manager problem. It is,
however, annoying and happening all too often. I hope it will be
fixed before the final released. The final release is said to be
able to enable the effects automatically, if the system can manage.
One other addition is the Cover Switch window switching
effect."