Update on mine....
It is a week 25 build.
I was looking at the screen on my iPhone 4 in comparison to my 3GS that I gave to my wife.
It looked a little more warm or sorta had more of a yellow hue to the screen.
Last night after having it for a couple weeks now, I did a comparison of hers to mine using the blue background in the TOMTOM app and boy what a difference.
The 3GS looks really blue but my iPhone 4 looks more of a turquoise color.
I dont have the yellow blotches but it does have a more yellow or warm tint to it.
I then was in the Apple store today and sure enough, the demo ones on the counter dont look anything like mine.
I would use the brightness page as a reference.
Ill probably be returning it and hope I can get a new one and not a refurb.