Like many, I had the yellow bar at the bottom of the screen. I noticed that it was more noticeably when the iphone was hot. So I went to the apple store and they were happy to exchange it. Now here is where the issue starts...the new iPhone screen does NOT have the yellow bar, but the overall color temperature was much more warmer or yellow then every display model at the apple store. I went back upstairs and showed the Genius who agreed and was happy to exchange it again. The one he brought back was the same. He took out his iphone and it was like all of the display models...vivid, bright and whites look white. He said he could exchange it again, but I told him I would see if I noticed it after a couple days. So FYI, the replacement phones at the apple store may have dimmer more washed out displays. If I were you, I would not compare your iPhone to the display models. You may end up in my situation.