Here is the problem with that article, if the device they tested shows up an almost perfect rendition and all devices were equal then fine. As we already know, the displays in the iPhone 5 can vary quite a bit and so another iPhone which has a screen that is visibly different to their test subject will show up a different set of results. Because Apple are using different displays, they would need to individually calibrate each screen at the factory to ensure a constant output. This clearly is not happening, the screens are capable of displaying an all-round better image than the likes of the iPhone 4 as per that article however if different backlights colour the output and this is not corrected, the colour balance of the displays will differ as we are seeing. Unless white balance is corrected or they use a single source of identical LCD/Backlight combinations, we will always have this potential for a difference.
I'm not knocking that article by the way, the tests are wholly valid but unfortunately, only for the device they tested. It does go to show what the new display is capable of though.