Hi,
What were the results of the 120W?
I too purchased a unit from china, the LED technology there is almost a decade ahead Id say and the pricing is ridiculous.
I will have a 300W unit coming sometimes next month, and will test out the abilities.
The company I deal with also has 600W systems, but the problem is nothing is UL listed, everything is only CE and ROHS which is European standards I believe.