A little more research on this led me to this post in a forum:

"Last night, I spoke with my LCD PHD friend a bit more about this...

He said that OLED is made from a light producing organic plastic. Thus there will always be some variation to the brightness that is displayed throughout the screen. The only question is determining if yours is good enough or there is too much distortion. So all of the claims about getting replacements that are worse or just as bad, are right on. You just need to determine the relative quality of your phone's screen... but most people don't have anything to compare against."