This was my dream lens since the mid 1980's, but it fell into the category of unobtainium because of the outrageous price at the time. My infatuation with this lens never really ended, and is the reason that I have purchased two AFS200-400mm f/4 VR's in the past three years. The first lasted two years until I finally became too frustrated with how my lens handled atmospheric interference (lack of detail when shot at a distance). I thought I was done with the focal length until this winter came along. While I thoroughly enjoy shooting wildlife w/ my 300mm f/2.8 AFS-II w & w/out converters, I missed the flexibility of zooming out as birds flew towards me. Because the 200-400mm f/4 VR's have lost favor to the much lighter (and lesser-build) 200-500mm f5/6VR, these pro AF optics can be had for a song... well, not quite. Anyway, I bought a second one two month ago. This lens was produced late in the VR-1 production and seems to be much better at a distance than my first lens...
Anyway, my point.. the combination of focal length and relatively fast aperture makes the 200-400mm lens an amazing all around lens. If you like manual focus lenses, I can only assume that you will love the lens that you are assessing.