How important is that gray uniformity? I watch a lot of college football and that's about it.
From Rtings
Gray uniformity describes how well a TV is able to maintain a single, uniform color on the screen. Uniformity issues can look like darker patches around the screen, with corners and edges especially susceptible to looking darker than intended. Its particularly an issue for sports, where darker patches on the screen can affect the look of playing surfaces.
To evaluate gray uniformity, we take a photograph of the screen while it is displaying a single, solid color. Using that picture, we calculate both the standard deviation of the color values of the pixels across the entire screen, and the number and severity of darker patches in the center of the screen (where they matter most).
When it matters
Youre most likely to notice gray uniformity issues while watching sports, since playing surfaces are usually large stretches of a single color. Dirty screen effect will also be most obvious when there is a panning shot during sports. Most non-sports media tends to be a bit more varied, so you shouldnt have gray uniformity issues with anything else unless your TV has particularly poor uniformity.