I've had a 24" fixture over my ADA 60f for about 3 months now. I used a combo of the royal blue, red, and green LEDs with the 5700k:
W W W B G R W W W B G R W W W
(W=5700k, B=470 Blue, G=Green, R=660 Deep Red)
The green brought the color closer to 9000K and away from the pinkish color (which I hate). I have it dimmed to 30-50% and 12" above my tank (45-degree optics), and my plants have been happy--really happy actually. The RCS look fantastic, too. At first, there was a slight disco effect, but oddly, it went away.
Overall, great service from Nick, great product; I'm very happy with it.