I have upgraded my S400 3 weeks ago, the acclimatation program is ending today. I have ordered 3 led modules instead of 2, and I think it makes a difference.
So far I am happy with it, the color setup provided by RedSeaKev looks great. I don't see any difference on my corals, the only difference for the time being is that my chiller does not need to work at all, and that is great!