I just received a new PW - batch 603! (The second string of numbers is 1603) And the screen is gorgeous! Uniformly white! And the shadows at the bottom of the screen where the lights are located is quite minimized!
My first PW was a 501 batch [I ordered it immediately] - the shadows at the bottom of the screen are quite pronounced, and the screen was not uniformly white - more "muddy" appearing. I kept it because it had none of the color splotches that other members had described.
When I place the 2 side by side with the same light setting, the improvement is quite obvious. I'll try to take some pictures this weekend & post them here.