Nikon's explanation of "factory refurbished" can be found here.
Three things to note about refurbished Nikon product:
- The warranty is reduced from one year to 90 days.
- Generally, no exchanges are allowed on refurbished products.
- Active rebates for the product as sold new almost always don't apply.
Personally, I'm not a big fan of reconditioned equipment, especially at the high end. Yes, I know the discount might be enticing, but you're essentially buying a used product that Nikon has reconditioned. It might have never been used, it might be slightly used, it might be fairly heavily used. A 90-day warranty means you'd better test and use the product a good deal very quickly to establish that it doesn't have a defect that needs repair. With most Nikon camera repairs running US$300 and up these days, failure to find any inherent problems quickly may mean you'll be paying all of what you saved in the first place. Moreover, your only real recourse would be to have it repaired, as there's usually a "no replacement" policy if you find a problem with the product.
Recently, one pro I know bought a refurbished Nikon camera in order to save money in his upgrade process. He tried to shoot an assignment with it only to discover it had a problem that needed fixing. In the end, did he really save money? No. Had he bought a new product from a local dealer, almost certainly the moment the problem was discovered his dealer would have been able to swap out the defective unit for a new one. Instead, not only did he lose the assignment, but the camera had to go to Nikon for repair, which took it out of operation for a period of time.