The D700 is a very robust body. Mine has been working perfectly since I purchased it about four years ago. I think you are correct regarding the value of Peace of Mind and the choice is very dependent on your comfort level. If you buy a used camera from an individual you have to have some trust that they took good care of the camera. If you buy from KEH or other Dealer, most stand behind the used equipment that they sell and provide a three to six month warranty on used gear. Of course this is reflected in the price. Good Luck with your decision. Good Luck and Enjoy your Nikons!