I gave Compiz another try today after a good many months. It's in Portage and it installed easily, as did Compiz Fusion. Which itself is a change from the last time I tried it.
Compiz still never works quite right with KDE. The desktop pager and taskbar are always wonky. However there are some patched versions of kicker applets floating around which make kicker's pager and taskbar work correctly. Though I'm using KDE 3.5.9 and those apps are meant for older versions of KDE, they work fine for me.
I've been in love with kwin for a while now; it does exactly what I want. So I'm questioning whether I want or need to switch to Compiz at all. Aside from gratuitous graphical effects, does Compiz do anything kwin doesn't?
One "yes" to this question is the way Compiz lets you view and manage virtual desktops. Of course there's the infamous Enormous Rotating Cube which at this point in my life I can accept as totally worthless other than to impress people. But Compiz also has a flat desktop "wall" view which is more minimalistic and very nice.
Something I do often is throw windows back and forth between desktops. Kicker gives you a tiny little pager which you can use to drag windows around between desktops, but my 2x4 grid of desktops is far too tiny for this to be easy. I could make the pager bigger but then kicker itself would grow to monstrous proportions and hog far too much screen real estate.
Or you can right-click a window and move it to a desktop that way, but then you're almost working the dark, not quite sure what the target desktop is going to look like once this new window plonks down onto it. (And right-clicking and navigating popup menus is too slow for my impatient self.)
Compiz on the other hand gives you a huge view of your desktops, and this desktop view stays out of the way until you activate it (by putting the mouse in the corner or by hitting a key combo), which is exactly what I want.
You can drag and drop windows between desktops on that thing. You can also easily see which apps are open on which desktops, something that a tiny little kicker pager never quite conveys. And it looks as good as any fruit-based desktop OS, which it likely is copied from to begin with.
Compiz actually does have quite a few nice features like this that can improve your window managing enjoyment a bit. Compiz also has a lot of incredibly annoying and distracting features. The good thing is that you CAN disable the wobbly windows and rotating cubes and other distractions. You can set windows to gently fade in and out of existence rather than explode into giant fireballs. You can disable the silly window opacity and motion blurring plugins. Yeah you can make it snow on your desktop and have your tooltips beam onto your monitor like Star Trek, but you don't have to.
Compiz also has a nice rule-matching engine to let you manage window placement, size, stickiness, etc. based on window names or classes or other attributes. It's not quite as easy to configure as kwin but it's usable. Compiz lets you configure shortcut keys for everything too, which is essential for me.