sorry, LONG post! But, first time posting with my ipad
I've watched this thread with some interest. It mirrors the thread on iPad 2 backlight bleed (similar on the iPad 3), iMac yellow blotches (my iMac had a bottom half of the screen that was slightly yellow tinted) MacbookPro screen uniformity (plenty of forums posts out there where people are not satisfied with their Pro's 'professional' screen - even through pro is Apple marketing spiel).
Also, my best-in-class (according to the experts) IPS Panasonic 3D tv has a bit of backlight bleed.
When you put all this together, there are two connections, a degree of manufacturing imperfection, and limits of the display tech.
I'm now convinced that in most cases most LCD & LED screens will have a degree of unevenness according to the current mainstream tech. Put the iPad, Macs and TV complaints together and the evidence does not point to poor manufacture in most cases, but the limits of current flat screen display lighting for the ENTIRE industry. In my experience Apple devices are above average in this regard, though the iMacs can be pretty poor. But, when my class leading TV, my iMacs, my MacBook Air, iPad '3' all have varying degrees of bleed and unevenness I don't think I'm unlucky, just that this is the tech we have right now.
For example I went through FIVE iMacs (!!) until I realised I was wasting my time. It was at this point that I found an NEC display forum that described how IPS screens ARE prone to a degree of colour blotchiness unless VERY carefully manufactured, hence the huge cost of NEC professional monitors. Actually doing some digging it seems IPS is best for colour consistency and viewing angles, BUT 'rubbish' TN screens do tend to have better grayscale (and therefore white) uniformity when viewed dead on. It also should be noted that IPS DOES NOT guarantee less backlight bleed, again unless great care is made in the design of the display bezel, case, and other elements.
The problem is there is no way Apple displays could be manufactured to necessary tolerances and be 'affordable' given Apples profit margins and manufacturing process. Really, given what they charge Apple is doing OK, I think, in general screen quality, no better than a Sony, but no worse.
SO, Just because Apple stuff is well marketed, nicely packaged, and uses fancy terms like 'retina display' does not make it professional quality. I mean, it's mass produced in Chinese sweatshops! You can't compare it to a Rolex that is a handmade watch, or high end NEC screens made in specialised factories. My first ever Mac, a g4 PowerBook, was manufactured flawlessly, but then it was produced in far less numbers.
This is not to say there are not VERY bad examples; I wouldn't accept some of the screens posted on here. But I do think swapping more than once looking for perfection is a waste of time. Very few are going to be awful (so if you find a bad one do swap) but very few will be perfect either given the limits of IPS tech.
Oh and jut to show that I am not dismissing your problems, this morning I swapped my new iPad at the Trafford Centre as it had a bloody bit of something under the glass in the middle of the bottom third of the screen. That bothers me much more as because crud seems to get stuck under a fair amount of iMac, MacbookPro and iPad screens (one on display had it as well) so it really is pot luck. But even with that annoying problem I'm not going to inspect this new iPad for problems, if I don't spot anything in everyday use then I'm happy.
Interestingly, this one DOES seem to have a slightly better viewing angle and white uniformity, but at the same time I'd not say the one I had before was awful (compared TN screens).
SO, the issue is getting one you are happy with as long as you have realistic expectations.
Of course, if you were to say "I've spent £400 so I should expect perfection", your right! You should be happy with your purchase, that's why you can get a refund. But, thinking you'll find perfection from Apple is a waste of time. I never had an iPad because I found the backlit bleed excessive (but understandable) yet on the new ones the resolution makes it worth living with for me. But knowing how they are made I expect some flaws.
In the end expecting perfection from Apple devices is impossible. The fault IS with Apple as all this is the result of their well established reality distortion field. By given the silly profits Apple makes on stuff if we want them to be perfect we'll have to pay more.
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P.s. comparing with iPad 2 screens is also pointless as these are obviously different screens manufactured in a different way (Apple wasn't able to leverage Sharp's new tech unfortunately).
