Recently purchase the new Nikkor 600mm f/4E, FL, ED, VR Prime Lens and I love it. The clarity of the pictures coupled with a very fast focus make it a wonderful nature lens. Even with the reduced weight it is still a large and heavy lens, but I have been able to use it free hand on many outings.
Clarity; Auto Focus; Quality of build
Heavy, I found it susceptible to moisture; I had the front glass fog up on the inside the lens slightly after indirect exposure to damp conditions for about 20 minutes; It cleared up withing 20 minutes at home; I have not had this issue with other lens.