Motivated by night shift on the iPhone, I just downloaded f.lux for my old macbook pro running El Capitan. I can't decide if I like it yet. Certainly it seems to be easier on the eyes. When I switched back to regular mode, it felt very jarring to my eyes. Not sure if it helps sleep yet. I've had it only since yesterday evening. However, if I want to watch a movie, then I have to disable it, or the colors in the movie look weird. Do you use f.lux and what's your experience with it? I am especially curious if someone used it for a bit and then decided it's not working for them.