Contrast Ratio – This is a ratio depicting the brightest white and the darkest black. The bigger the difference between these two numbers, the better. However, be aware that some manufacturers use “dynamic contrast ratio,” which is a test of the contrast in ideal conditions, whereas other manufacturer’s will list the “static contrast ratio,” which is a measurement of the contrast in more real-life conditions.
Brightness – Also called luminance, this term refers to how much light the screen can produce. It is measured in candelas (cd/m2), but all you really need to know is that the brighter a screen can be, the better you can see the images on the screen in a brightly lit room.
Hope this helps.
400 brightness is pretty good. 800:1 contrast is OK for an LCD, but not great.