I've had mine for almost four weeks now. It will actually be four weeks on Thursday of this coming week. It's a week 21 that I bought at Target. The screen is very uniform, but it is different from any other screen I have seen on one of these new ones. In fact it is very comparable to my iPad 2 in how it handles gray colors. When compared to my wife's new iPad, the gray is much lighter in color. Her gray is darker, and almost looks a little blueish. I am not sure which I like better. The bluish color makes the whites look a bit brigher and whiter. On mine, they look every so slightly yellowish. TBH, I am not really sure if I have one of the screens that's yellowish, because I've never seen one before. The only yellows that I've seen on screens are in patches that look more brown.
Another friend took the plunge the other day and got one. I suggested that she go to Target to pick hers up. It is also a week 21 DY, like mine. Her screen looks more like my wife's screen with the slightly blueish tinged grays. But it also has a green tinted left edge. So while screen uniformity does appear to be getting better, there are still issues out there. As we're at week 21, I am guessing that there will always be some issues around. Though they have come a long way from my launch day iPad. That thing was a complete disaster. If it is anything like the iPad 2, there will always be differences between the screens. Even in November when I was attempting to buy myself an iPad 2, I saw noticable differences between the couple that I tried. I guess that for whatever reason, there's just no way to make them all exactly the same.
Anyway, other than the thing with the gray colors, mine has been great. And I'm not even sure that the gray thing is actually a thing. When compared to my iPad 2, the grays are almost exactly the same. I am doing a comparison right now with the brightness setting screen. They look almost exactly the same, aside from the better resolution of the new iPad. When I look at a completely white screen, the iPad 2 looks just a bit more yellowish than my new iPad.
Ha. My friend saw the greenish tinted strip along the left side and asked me to trade mine for hers. Even swap. Though I do like the way whites look a bit better on hers than mine, I worked hard to get one that was uniform. I don't want yet another with a darker left edge.