When comparing XFWM vs Compiz, the Slant community recommends XFWM for most people. In the question“What are the best window managers for Linux?” XFWM is ranked 12th while Compiz is ranked 16th.
Ranked in these QuestionsQuestion Ranking
Pro Can choose to open windows at center of screen or edge
Pro Integrated compositing manager
XFWM has an integrated compositing manager, though it does have screen tearing.
Pro Left-half/Right-half window snapping
XFWM has a built-in option for window snapping.
Pro Great and beautiful theme support
It's very easy to create themes.
Pro Lightweight and desktop independent
Cube desktop is appealing to some users, in addition to many of the other visual effects Compiz can manage.
Compiz has plug-ins that can be enabled / disabled in order to alter its behavior.
Pro Has great wobbly windows
Pro Unity Shell
Unity Shell is a plug-in available for Compiz and so is needed for Unity to exist. Unity is also the default desktop environment for Ubuntu and is arguably the most popular Linux distro to date.
Con Composite manager has screen tearing
The included composite manager in XFWM has screen tearing.
It should be mentioned that there's a workaround though:
compton --backend xrender --vsync opengl
Con Heavy window manager
Compiz is one of the heavier window managers around: it uses higher amounts of RAM and CPU than other options
Con Crashes frequently
Breaks in the system are frequent.
Con Requires 3D acceleration
If this is not present in the system, it will offload from the GPU to the CPU.