One suggestion, that no one has seemed to be able to tackle in the jQuery Accordion making community, is the slight bump that happens at the bottom of the accordion. You notice it slightly on your first example but can see it a lot on your second example.
You'll see on the apple site there is no bump at all. It just slides without effecting any other areas of the menu. I think this is because we are showing/hiding heights and the apple site is using absolute/static/relative positioning to get the effects. Thoughts?