You found the exact links that I had already read, but thanks for the effort

Neither told me much about the contributor profiles, and the second link said at least one thing that I think, even at that time, was completely wrong (that most contributors of both projects do it b/c they enjoy it - implying volunteer).
Lucid is the first time I've regularly used Ubuntu for awhile, and here compositing DOES default to compiz (and it is slow - click on menu and, for me, there is a very apparent lag), but you can enable metacity by running "metacity --replace --composite". The menu lag goes away and you have compositing with a few effects (clicking on an app icon in the panel causes the icon to enlarge and become transparent very rapidly, minimize effects, etc). However, if you want a tear free window moving experience use mutter
Best/Liam