tedster - 5:55 am on Jan 27, 2001 (gmt 0)

An added factor to consider: the jumpiness is due to processor speed. I was viewing on pretty old equipment, a 166Mhz. The faster the processor, the smoother it will look.
So, a lot depends on your target audience.

Also, I'm sure you'll notice this sooner or later, but right now the menu disappears altogether at the bottom of the page. I guess there is a CSS container that needs to be lengthened.

By the way, we've been working on a traveling menu something like this for our company site. Haven't got it moving any better than you do.