The next time you go shopping for an HDTV, bring a USB "toolkit" of images to help evaluate the screen and image quality. You'll get a better sense of any issues with the set than you will watching gaudy demo-reels.
It's tough to get a clear idea of what an HDTV picture looks like from the showroom floor. Showrooms are poorly lit, the video is usually too bright and over-saturated, and the viewing angles are often less than ideal. Even with that stacked against you it's possible to get a sense of how well the screen performs with a few simple tests.