Maybe it's just me, but Twilight never felt as pleasant as f.lux and redshift do on my PCs. Instead of changing the screen color, it seems to add a red layer over the content.
If you've got a phone supported by CyanogenMod, it has a very nice mode called "LiveDisplay" which will adjust the phone screen's colour temperature on the fly based on time of day and both the brightness and colour of the ambient light.
