Hi Paul,
I haven't checked in onScriptaculous lately, but IIRC it does have a lot of useful effects. Dojo have a host of different fx and animations as well. What might be different in Dojo is that the animation package is generic and can be applied to almost any kind of transitions.
It's possible, for example to make a transition between two CSS classes, or to drive another kind of thing entirely ith the callbacks.
If you download the Dojo source (or check out svn anonymously - the docs is on the main site at the bottom) there are
unit tests in the dojox/fx/tests folder.
Cheers,
PS