One thing to keep in mind for those who frequently shoot handheld at low shutter speeds (1/4 - 1/60): is there a difference in “keeper” rate between smaller and lighter cameras and their larger brethren?
There are a number of reasons that a Nikon D3 might be able to manage a better success rate at low shutter speeds than the D700:
Greater mass means greater stability; any motion tends to be better damped better with a larger camera.
Ergonomics—with the larger body of the D3, I can wedge it against my shoulder naturally; with smaller camera bodies like the D700/D300/D70, I must contort my shoulder upwards—awkward, and quickly fatiguing. With the “shoulder wedge”, the camera is braced firmly against the shoulder/forehead/hands, making for terrific stability. A larger camera also balances better on some tripods when larger lenses are used.
Shutter and mirror—the D700 has a different shutter and mirror box than the D3. It’s likely that the D700 has different damping characteristics than the D3 (“shutter slap”). The “danger zone” for mirror slap is the 1/8 - 1/30 sec range, depending on the camera (see The Sharpest Image)
Excepting the ergonomics issue, these items are speculation. But my handheld shooting experience with the D3 suggests that I get more keepers than I ever have before. Would that be the same for the D700? Something to keep in mind if you are contemplating the D3 vs D700.