You used to be able to go to a department store and purchase a television just based on the size you wanted. Now there's a lot more to consider, especially when it comes to 3D television. Just as with any appliance or piece of technology, the quality of passive 3D TVs depends on the manufacturer. Popular manufacturers include LG, Mitsubishi, Panasonic, Samsung and Toshiba. The quality of the picture depends on the type of technology; for example, there is plasma, LCD and LED. Each has its pros and cons. But one of the main differences actually comes in the glasses used to view the 3D movie or TV show.