Just received mine back from Nikon mission control (Service) in NY. I have just started to shoot some shots to check out if anything has changed.
According to the Nikon paper work, firmware was upgraded, ccd cleaned, exposure and focus checked. Exposure was within their standards, says nothing about focus.
Test shots so far show slight under exposure, HOWEVER, all seemed to be sharper. (or I am just really glad to have it back) I am going to perform testing the next few days on various test subjects and situations. Will let all know it it passes the grade. IF not, it also will go back to the dealer for an exchange.
If QC is an issue and if service is not stepping up to the plate, we need to make Nikon Senior, (who ever that may be) aware of this situation.