I came here to post just that. I don't use f.lux because it doesn't ship packages for anything but ubuntu... The beauty of redshift is that you can just stick it in a shell script and start it with every desktop session.

I have been using it with the following parameters: redshift -l <my latitude>:<my longitude> -t 6500:5200 -g 0.8 -m vidmode

This results in slightly reduced gamma all the time but only a moderate redshift that doesn't offset colours too much. I have it set to autostart and I really don't notice it being there, however I do notice it is missing when switching users or OSes!

RedShift is pretty nice, easily configurable and you can just add it to your wm's startup. Pretty stable too, been using it for an year now.

Well, you can use f.lux too. I prefer redshift because of its CLI nature.

Another vote for Redshift. Use Flux on work PC and Redshift on laptop. The colour transition seems to be a lot more subtle with Redshift and I find it easier to adjust. On the other hand, the change feels very sudden with Flux. Often use my laptop in work, but I suppose it could well just be a difference in lighting between home and the office, as others have mentioned. Maybe my eyes deceive me.

redshift has constant problems with it's geolocate service in recent versions of Ubuntu. Not sure what the issue is, but you can specify the longitude and latitude to circumvent it. I use, for example:

    redshift -l <long>:<lat>

I've not had good luck with the f.lux port for linux.