I think you are missing one important factor here. Addressing the way corals grow or don't grow is one thing. How about the guys like me who just don't like the way a tank looks under LED light? For me, I do want good growth, however the look of the tank in my living room is at least as important as how good things grow. LED lighting in every instance, to me looks too sterile. LEDs do not capture the look of a tank lit well with halides. And no I am not just talking about shimmer. Plenty of LED solutions out there create a nice shimmer effect. LEDs just miss a lot of the intermediate frequencies between the frequency that the diode is designed for. A lot more peaks and valleys in analyzing LED lighting over halides. Again, I wouldn't argue about growth differences, for me it is purely aesthetics looking into my tank. Halides look better. Period.