The smaller the lux number the better the low light performance. 0.002 is better than 0.02
The smaller the "F" of the lens the better the low light performance. F1.4 is better than F1.8
The larger the sensor the better the low light performance. 1/1.8" is better (bigger) than 1/2.7"
The higher the megapixels for the same size sensor the worse the low light performance. A 4MP camera with a 1/1.8" sensor will perform better than a 8MP camera with that same 1/1.8" sensor.
720P - 1/3" = .333"
2MP - 1/2.8" = .357" (think a .38 caliber bullet)
4MP - 1/1.8" = .555" (bigger than a .50 caliber bullet or ball)
8MP - 1/1.2" = .833" (bigger than a 20mm chain gun round)