I love redshift as well. I actually keep it 24x7, and my eyes don't get tired at all even after 12 hours of programming. Nowadays, turning off redshift feels like an attack on the eyes.

And no, reducing brightness on monitors doesn't have the same effect. I recently upgraded my monitors to 600nits brightness from 350nits and there has been no change in comfort level with redshift but without the redshift, the old monitors (and the new) stil feel very hostile to eyes.