Unless you have a trained eye, it is difficult to see more than color balance differences in sets. Hooking up a dedicated BluRay player, a good HDMI cable, and a good movie source is the best way to evaluate a set, but most showrooms cannot accommodate such a request. So you must look for differences in the signals simultaneously delivered through their video signal distribution system that CAN tell you something about the set.
Most people are familiar with what is called JPG noise in digital pictures, an artifact of a compression and decompression process that leaves speckles in a picture. In HDTV, this video noise appears along the outer perimeter of objects. More easily seen in slow moving things like people walking against high-contrasts backgrounds, a video noise appears highly visible on cheap sets and less to invisible on better sets. Look for this noise and you will quickly sift out the sheep from the goats. Lower speckles means a clearer picture.
|Look at the hair clarity on the RH dancer or belly speckles on the LH dancer to see the effects of video noise|
Black (or contrast level) is another test you can see pretty easily in such an environment although it is best detected in a darker room. When the picture drops out such as a moment between commercials or in a really dark night scene, marginal black representations appear gray. Overly black situations will not show enough detail in darker images or even create weird colors in the shadow or black areas. The center image below shows good black levels while the L image shows too little and the R image is overly black.
Do not be too quick to judge color accuracy and black levels since all sets are calibrated from the manufacturer to give the most wow but not the best color and black level. Buy a test DVD, such as the Digital Video Essentials "HD Basics," and once you narrow down a set, ask the salesperson if you can reset the display settings from its instructions. It takes a few minutes but the results may surprise you as to what a well-respected brand name set can and cannot do.
All sets are compromises but as mentioned Plasma sets tend to find their ways into more demanding homes. The only issue with Plasma is that such sets run pretty hot compared to the others (LCD/LED) and will put an additional load on your home A/C. I have measured as much as s 20 degree F screen temperature difference between models using a hand-held infrared thermometer. This is a parasitic cost of operation that like a tube amp and preamp you just live with if you like what you see.