What is the difference between the blue shaft and the black shaft of the mechanical keyboard?
Personal feeling, if not typing too fast, or green axis better, a strong sense of paragraph, sound is very sensitive, especially a sense of rhythm. Black shaft feels long, hands a little tired. As for the backlight, if you can comfortably, feeling just a backlight decoration really.
The black axis is good for games like Starcraft 2 and dota. The red axis is suitable for playing CS like fps. As for keyboard backlighting, I don't know anything about it.
Green axis feeling is pressed down "Ka kraaa Chi", the feeling is a black shaft according to the end without the sense of paragraph. The best way to play games is the red and black shafts. Can quickly input, unlike film keyboard that press on the paper shell feeling. The feeling of the black shaft is pressed on the soft spring (it appears to be pressed on the spring -!). The red axis is a stronger sense of the paragraph than the black axis.
