I also deal with Memory Express and have found them a good store. My relationship with London Drugs is long-standing so I know people there. I'm sure that helps. When I first discovered the sensor problem I contacted Nikon and was promptly told by them to ship to Vancouver. Upon going to LD (being too "cheap" to pay insurance and shipping) the rep there - who has a lot of experience - told me Toronto was a better facility and also faster. Well, he should know and as LD was guaranteeing the work I just left everything to them.
My experience has left me feeling positive about Nikon and their dealer although more so about the dealer which is a bit worrisome. Any premium manufacturer such as Nikon can make a mistake from time to time but for $3k I agree there ought to be premium suppport as well. After reading your report and many others the impression is obtained Nikon response and the quality thereof is apt to be spotty. I read some other postings that the Toronto service was fast and good with some people there getting their units back in 3 days. Going by the service log returned with my D800, mine was actually in the shop about 4 days.