KDE is feature-rich. Is it as capable with the cubes and the special 3-D effects?

Yes. Search for them...

well, kde cannot do everything compiz can (compiz has a gaziljon desktop effects) but the most sensible ones are also available in kde, including the cube.

kwin as a windowmanager is more capable than compiz, as i have experienced as a advanced user of kwin's window management features.
I always drop back to kwin after a while when using compiz.
and now with kde4, i don't use compiz any longer

You'll find that most of the functionally useful effects are present in kwin like desktop grid & present windows, but it doesn't have all the eye candy of compiz, but it does have snow.

Riinse wrote:...and now with kde4, i don't use compiz any longer

Ditto that one.
I used to use compiz quite a bit with kde 3.5, not I don't see any need to even install it when using kde 4. As I see it compiz will provide the innovative edge for those interested in all of what's possible in terms of desktop effects and compositing, while Kwin takes a step back and carefully implements those features that make for the best general user experience. Kwin's effects seem to run smoother than what I recall from compiz, but that may be biased based on my not having used compiz in at least a year now.

Probably the biggest missing feature of kwin is the lack of support for mouse based input events to control things like the zoom plug-in. It's nice to be able to use SuperKey+Scroll-Wheel to zoom in and out, but this can be worked around with the installation of a program to map mouse events to keyboard events.

Also screen artifacts such as when some windows are opened, you can have garbage being rendered for a moment before the window is fully rendered. Especially noticeable when opening the K-Menu.

Also window resizing is slower than with Compiz.

The wobbly windows plug-in's physics doesn't feel quite as nice as Compiz's one, but you get used to it (and it's no big deal anyway.)

KWin has come a long way since 4.0 and has been a fairly adequate replacement for Compiz for a couple of releases now as far as eye candy is concerned, and of course Kwin **** all over Metacity as far as the most important window management functions are concerned.

Thankfully KDE users have the option to run either one depending on which features they value the most.

Should it do everything Compiz can? I'd say no. Some of the effects in compiz are ridiculous and pointless.

It looks like Compiz has a much better memory footprint than kwin.

But compiz is much worse at being a general-purpose window manager than KWin or metacity...

einar wrote:But compiz is much worse at being a general-purpose window manager than KWin or metacity...

I wouldn't say much worse. I do like the window tabbing of KDE 4.4 but will be going back to Compiz for a while to grab some accurate metrics for clear comparison.

Why I'm there I'll be revisiting the per application window management functions of Compiz. Ultimately as long as it provides the window management in order support what I'm doing where the app itself is left wanting in some respect I'll stay there until KDE 4.5.

Specifically at the moment, Boxee doesn't work well with an nVidia based system with Twinview enabled. This is where per app forced settings are a life saver.