Any updates regarding your exchange for a new set?
I am also experiencing some banding on either side of the tv, mostly visible on a uniform light colored image, nothing too serious during actual program watching but wanted to confirm if it's typical of all the 90" panels.
Everything else is working just fine on the tv,aside from the screen inconsistency you wrote about, so I wouldn't want to risk getting a new tv, only to find other issues besides the banding.
And I wonder how much better overall is the 657 over the 745, in terms of picture quality and useful features?
Not sure that anyone has had the opportunity to really compare the two, but just thought I'd throw that out there, in case I did decide to make a warranty claim and they offered me the choice.