Not to be a nag, but when I read about how hard it was to get right I'm almost expecting that they will have problems as well. I'm not only thinking about how the sensors will fare over the long term, but also how it will interact with a plethora of screen protectors and other aftermarket items.
No idea why anyone has ever felt the need to use a screen protector - cases, sure, thats a matter of choice, but there's never been a genuine reason to cover your screen is with a screen protector - this stuff doesn't scratch easily AT ALL - i've had every iPhone since the very first and not a single one as scratched (and i've never used a case on any of them either) and I don't treat them with respect what so ever (i've dropped them face down on concrete/roads many times). Apple work hard to get the feeling of touching the glass just right and then people go and put those ill filling screen protectors with bubbles and lines and weird feeling over the screen - I don't get it?! Even if you got a scratch it'd look better than the edge of the screen protector going around the home button, they're disgustingly ugly.