Logitech TRACKMAN FX

This is an old model of Logitech Trackball. From long time ago, they just stopped making this model anymore.
It costs me a lot to get an used one on eBay, even more expensive than a brand new Logitech current model.
Is it worth? You have to try on your own. Then you may realize why they charge so much even for an used one.
Yabee...