Poor quality display on some iPhone 5 ( and 5c/5s?) units

Question

I'm on a family plan and as such I have multiple iPhone 5 phones.  I noticed that starting with the iPhone 5, many of the displays were visibly different than others.  For a long time, I thought the only issue was the vertical lines (interlacing) that many have reported ad-nauseum on these forums.  Yes it's a problem, but it would turn out it's not the only problem with these displays.  The other problem (and this turns out to be an even larger one) is that they are not even coming close to supporting the color gamut of the "good display" (i.e. the one that does not contain the interlacing lines).
I've seen reports of the interlacing occurring on 5s units as well, and so I can only assume they also share the trait of having the horribly inadequate color reproduction.
Below, please see the image of two iPhone 5 units.  The black unit has the good screen, insofar as it does not have the vertical interlacing lines visible and you'll notice the color wheel is displayed correctly.  The white unit has the visibly inferior display and lo and behold, it also can't even properly display the color wheel.  Notice the abrupt shift in colors and banding present in the image.
Zooming in on the color wheel makes the inferiority of the display on the white iPhone more apparent.  I have read so many reviews about how great the iPhone 5 display is.  But it's not fair that they only review the good screen.  Then when we as customers get the bad screen we are left out in the cold, with reviews telling everybody how great the iPhone display is but with the reality being quite mediocre.
I hope Apple stops allowing such a wide variance in display performance across their approved LCD manufacturers.  I didn't run this test just for the fun of it.  I ran the test because I was noticing how lackluster the screen on my white iPhone 5 was and wanted to verify it to make sure I wasn't going crazy.
Hey Apple -- it's not a "minor thing".  Your cutting of corners does get noticed and it will influence your sales going forward as your competition improves.

Answer 1

My first 5s had a PERFECT Screen. Perfect color accuracy and no interlaced lines shown in the image. I got that phone replaced however because the camera module was rattling much more than it should and in fact felt loose in the phone casing to the point where a vibrating notification would set off a rattlesnake like rattle.
During the replacement process it's impossible to detect whether or not the display on the replacement units have the interlacing issue because the iOS 7 setup screens are completely white. After activating the device the Apple Genius has to process the replacement as a "Point of Sale" and your warranty is then transferred to that device. By that time it was too late for me to go back to my perfect display despite the rattle since that device was no longer "mine". I sat there at the genius bar for a good 40 minutes trying to show the genius exactly what the issue was with the new phone, and she just couldn't see it. Eventually I was able to get a flickering image up, which convinced the manager to let me go through another replacement. Alas this replacement also has the issue. In fact while looking at the display models in the store, about 3/4 devices had the issue, even the iPhone 5c.
I am going back to another apple store in my area next week to see if I can actually get a genius to see the issue and provide a replacement that doesn't have this issue.
I do believe however, when I was comparing my old perfect screen to the new flawed one, the perfect screen had really good calibration for the whites. The replacement had a distinctly warm feeling. If you're going in for replacement for this issue, open up a pure while image and compare it to the activation screen of the replacement. If the replacement has a noticeably cooler display but is not blue tinged then that panel probably does not have the interlacing issue that so many of us are experiencing.