That's a lost battle. Every tech product I've ever sent back for warranty has required that I pay for shipping to them. It would be tough to find one that didn't.
In terms of Nikon service, I've had nothing but good results. I also sent my d600 back for spotting, and they replaced the shutter and had it back to me in two weeks. In the past, I've had several lenses repaired. They have always been relatively fast, and even the out of warranty stuff has been reasonably priced.