Nikon 300mm F4

I have been looking for a short tele lens for both portraits and outdoor tele for my recently acquired D800 (I came from Canon 5d Mark II). Initially I was looking at 70-200 zooms and due to budget reasons, I skipped it. I bought a 85mm F1.8G and now looking at Nikon 300mm F4 lens. Any tests on this lens? Could anyone please provide their experiences with this lens (on D800 and other cameras)?

Sigma used to have a 100-300 F4 lens, but they seem to be out of production and I can see that a lot of people complained about focus problems.

-Madhu