I tried f.lux and do not like it at all; I don't think color temperature is the problem and my MacBook Air seems cheapened when it has a 1970s red tint to the display.
Since using Hacker Vision, I notice that I can turn my display brightness down to 2-3(again, a MacBook Air) which has the added benefit of giving me an extra ~40 minutes of battery life - very cool!
https://chrome.google.com/webstore/detail/hacker-vision/fomm...