My 2.5 cents:
From the picture it seems that the 4 buttons give more diffusion than the knobs - at least for the red, blue and amber. I can see the four leds behind the knobs for those colors while the green and yellow (orange?) knobs have nice diffusion. I like them better. Maybe I'm being overly critical, but since you asked...
Anyway, I second the guys' congratulations - excellent work. Now I wish somebody was just as active with the aluminum faces.