I was at Bill Voss' house yesterday and we hooked up the D120 to his rock vat. The light was approximately 2' off the surface of the water and he measured the PAR at 18" water depth and it was 150-200. 350 just below the surface.
I placed one next to a 400w dimmable halide yesterday and it lit the bottom of the tank with nearly the same intensity of light. At least it appeared that way to my eye and the tank owners eye. She is going to replace 2 Dimmable 400w MH's with 3 of these lights.
If these lights last more than 2 years, then they are the best value in LEDs on the market and should be called the "Game Changer".