The LCD (Liquid Crystal Display) consists of two parallel transparent plates. A thin layer of liquid crystal is sandwiched between these plates. These crystals are oriented when crossed by electric current and then produce pixels.
As for the plasma screen they are made up of encapsulated mixture of gases (argon and xenon). Upon inducing an electric current, the gases produce a light radiation which is then converted to yield 16 million colors.
The distance from the screen
Consider the place of the screen at home. The plasma does not exist in small sizes.
Lifetime and power consumption
Between 50 000 and 60 000 hours for LCD. Between 30 000 and 50 000 hours for Plasma. Approximately 6 hours for 14 years for both. Plasma technology consumes more energy (up to 20% more) to illuminate the pixels of the screen compared to LCD (high efficiency).
Plasma screen is still generally more expensive than the LCD screen (for an equivalent size). But the gap is narrowing.
If you're searching for a small screen sizes (15 to 36 inches), only the LCD technology are availble. Between 37 and 50 inches, the two categories are present
The image quality and defects
Colors / contrast / Pixel "death" / Fluidity
The plasma screens can get deep blacks: the contrasts and more details emerge on light or dark images. On the LCD, dark colors are made less efficient (light traces), even if the technology improves. Plasma restores colors more naturally (most degraded). It also avoids the "dead pixels", which may appear black or white on LCD screens (sometimes very annoying). The sequence of images may look more fluid on the plasma screens.
The viewing angles
Important if you are not facing the screen. Plasma TVs generally offer better viewing angles (160 °- 170° (vertical / horizontal)). LCDs distort the image more than the plasma screen.
The "burning" effect
This type of defect is specific to plasma screen. When an image remains static for too much time on the screen, pixels may be affected (especially in the first 200 hours of use). This defect is irreversible and causes loss of brightness in some places. If you use your screen to video games, LCD technology is more appropriate.
Plasma reflect external light sources. This defect may impair the quality of viewing.