So I went to the Apple store to compare my phone with the display models. It was roughly 50-50, with half the phones somewhat better and half worse. Looking it the screen at full brightness, it appears that Apple placed the LEDs used for backlighting the screen at the top, the area where it's somewhat dimmer. It appears to be a combination design flaw and quality control issue, with the light not properly diffusing right at the edge. My guess is that it's a result of using a low-quality display. The other thing I noticed is that no two screens had the same white point, although some screens were similar to each other. My screen has a slight reddish hue; one at the store had a horribly blue cast to it.
I should also add that I spoke with a Genius when I first arrived and he said that he and the other Geniuses did not see cause for replacement with my phone, adding that some could not discern a difference between the top and bottom portions of the screen. I thus opted to look at the display models in order to avoid getting needlessly angry and frustrated over a potential non-issue, and reached the conclusion noted above.
I will also add that I'm not not entirely satisfied with the outcome of my little experiment and may attempt an exchange in the future.
Just do the exchange in the future if you get a big scratch, dead pixel, or something or a loose button
my screen is also darker in the top left, annoying but just gonna keep it till after sept 30 to see if theres any changes