I get great results with my 70-200 VR on my d700. For my uses, it is more for sports and pj work which doesn't need sharp corners. It is a great lens regardless of the format.True DX lenses will automatically engage 24x 15 mm sensor area by default unless you tell it not to do so. It is in the menue.
The 70/200 is really not FX, but not DX either so it will bring up full frame. You will find the corners weak/soft at 180 +. Stopping down will not repair. You need the new 70/200 VR 11 for best results.