Interesting update on mine. I filled out the survey they sent me after the replacement phone I was given had just as many dark spots as the original. Apple actually called me back today to ask why I wasn't satisfied, and when I told them what was going on, they're having me go back to the store to get a different phone. They even called ahead to tell them to fit me in because of the roundabout way I ended up where I am (3 store visits just to find a store that had a replacement, only to have the replacement have an issue). Hopefully this new shipment of replacements does not have this issue anymore.