So, without an actual demo to play around with, I thought I'd put one together, both to see how easy it'd be to work with and to help demonstrate to others what to expect. What a better example than the drag and drop (especially since I'm finishing up a project that just happened to use drag and drop). Check out the example and check out the source code. I'll be going through and highlighting some of the interesting things.
Doing just enough
One of the things that I noticed in comparison to the Prototype/Scriptaculous (P&S) approach is that there's a basic framework for handling drag and drop and not much more. Where P&S can do much of it for you with just a couple settings tweaks, Mootools creates the hooks and leaves you to pull off the nitty gritty. Right off the bat, I created my new draggable.
$('dragger').addClassName('drag').makeDraggable();