Which Nikon 300mm f/4?

I'm a D700 shooter and looking to upgrade my telephoto from 180 to 300. There's a AF-S and a AF-D version of the 300 f/4 but there's a $400 gap between them on the used market. Is the AF-S worth the extra cash?

The AF-S has a built-in motor, vital if you want autofocus with the D3000/5000 series. It's useful, but not essential for the D700.