I had a chat this morning with a technical person in Nikon this morning, on the construction of the base and tripod thread of Nikon camera. It is confirm that the base, is made of a solid metal with thread made into it, and the base is screwed onto the body. This will be able to support the Blackrapid FastenR.
Now, if you use the D-ring of Manfrotto, it is questionable, as you know sometimes you might losen the D-ring, and the plate might fall off, so need to recheck often. The D-ring looks and feel thin, unlike the FastenR, so you might get the "will it fall off thinking". If your gear is D700 + Nikkor 50 mm f/1.4 quite safe. But not Nikkor 24-70 mm lens or those lens over 900 grams, chances that you might losen the D-ring.
Let's start continue this thread, with the types of combinations you have on FastenR.
To begin: I am on 24-70 mm (weigh 900 grams + for lens)