Finally! An upgrade to the venerable 300 f4 has been rumored for at least three years. Judging by the specs it may be well worth the wait. The old version was almost 9in(225mm) long and weighed 50oz(1.4kg). The new version will only be 6in.(150mm) long and weigh about half as much as the old one. They both take a 77mm filter. The MTF chart compares favorably as well.
I sold my old one a while back and have regretted it many times. It paired beautifully with the D7100. I've nearly given up on the upgrade and gotten a 300mm 2.8 several times when I've seen used ones. Now I'm glad I didn't. The size of the new one just blows me away. I thought it was a typo on NR but visited the Nikon site and that's what they've published. Paired with a D7100 and a 1.4x TC in the bag, that will be an awesome wildlife kit for travel.
The release is supposed to be next month so used prices of the old version will likely start to drop soon. For those who can't drop $2k on the new one and can live without the VR, the old version is already and will be even more so one of the best value for the dollar lenses out there.