After seeing the good screen, I realized that the bad one is suboptimal even when viewing straight on. The top of the screen is slightly lighter than it should be and the bottom is slightly darker. This is, of course, accentuated when tilted.
When you see the good one, it almost looks like a picture of a screen in its uniformity. ...if that makes any sense. The best example I've been able to find is in the shots at Engadget, like this one:
http://www.engadgetmobile.com/photos...nds-on/890582/