Depends on what you want. Some people like that stuff, other people not-so-much.
As for KDE integration...
There is nothing with Compiz and Beryl that make them KDE incompatable. People like to accuse compiz of being gnome-centric, but that is because the default set of plugins for Compiz include gconf support, which is Gnome's 'registry'. There is no reason why somebody can't write a KDE configuration plugin, but as far as I know nobody has done that yet.
I don't know about Beryl, they are off in bizzaro 'exploding flaming windows'-land and I have no clue what they are doing as far as configuration engines or desktop integration.
I don't think that KDE is very interested in support either thing either. They tend to have a very strong NIH syndrome.
But window managers are standardized nowadays. You have the EWMH which makes window hinting and other features standard across Metacity, KWM, OpenBox, and most other popular window managers. This effectively means that they are interchangable. If Beryl and/or Compiz has proper EWMH then aside from configuration tools these things should be a drop in replacement for the defaults in both KDE and gnome.