Had my 1st Genius appt today to try to sort out my 3rd new replacement 3G S which had a nice BRIGHT and non-polarized, slightly yellow screen (acceptable to me) but which was all washed out with poor contrast, and as you pegged it, I agree 100%:
+"Though all the colors seem true, their saturation is lower. Blacks seem more like dark charcoal when reading text in web pages (I do a lot of this), and their contrast against white seems lower. Even to the extent that it feels like there is a faint, low-lying fog hanging over the screen."+
So, the Genius listens to my explanation and history of how I got to have that 3rd 3G S and said he was happy to swap screens out for me since it was obviously a big deal for me. I noted 3 things here:
1) He didn't admit there was any problem, just that he noted it was a big deal for me,
2) He was willing to REPLACE the SCREEN, not just swap the phone for a new retail or a refurb,
3) He was very nice and patient and helpful.
So, after he disappeared in the back to personally do the screen swap, I carefully examined the screen, suspicious he might have just called his G/F and pretended to have swapped the screen. Nope, no tricks, he had indeed replaced it.
The washed out crap contrast poor blacks of my former screen were gone - this replaced screen had a deep, rich, high-contrast bright beautiful screen! Except, it was yellower and was polarized, exactly the same deal as what I had started with 4 phones ago!
#1 thing I cannot accept is that polarized screen where it dims to 50% if you don't look at the screen straight on, making it useless for my family to enjoy together.
So I'm basically confirming the trend others have recently noted here:
a) Former excessively yellow screens (some dim, some polarized) in the retail boxes now appear to be mixed with "updated models" having non-polarized screens that are bright, more appropriate warmer tones, but which are washed out with charcoal "blacks".
b) Screen replacements as was done for me can still dive into the old pool of yellow polarized screens.
c) The guy was very nice and offered me basically to keep the new screen, have him go back and put back the original, or return it for a refund.
Completely frustrated and exhausted, I chose to have him give me back the original display as I'd rather (for the moment) have a low-contrast washed out screen than a yellower polarized one.
As with others, I'm very happy with the level of patience and willingness to swap things from the Genius reps, but EXTREMELY UNHAPPY and way past impatient regarding the horrific quality of the current batches of screens.
OH one more thing I should note - if you're going to do any in-store comparisons to the display models, BE SURE to find a couple that you KNOW are good. The guy, as nice as he was, was very wise to take me to a very specific display unit that had a dimmer, yellower, polarized screen with which to compare the replaced screen with. So initially I was like "whoa this is better" then I realized what had happened and moved 3 phones down to the proper displays that were "per spec" in my opinion and then compared those. When he saw I was aware of what "proper spec" was, he offered me the aforementioned 3 choices...
So, they can be nice, but they can also be "wise", so watch out for your best interests there. Now, I guess I'll have to wait until I can find a store with a set of week 28's to try do a return/new purchase within the next 3 weeks. What a horrific mess and headache all this is. 4 bad screens in a row. For peace's sakes I'm glad this happened to mine and not my wife's - hers is PERFECT and she knows it - she flatly refuses to swap hers with any of the 4 I've had.