Color temp, different cct.. Due to different chips, different voltages, different phosphor recipe possibly.. different phosphor thicknesses, it could be a combo of things.. Its not going to be that big of a difference
EDIT:
HLG QB132 = 2835 4000k
Chinese QB312 = 5630 LM561c 3000k
HLG QB288 = 3030 LM301b 3000k
I think I saw lm561c on the Chinese and lm301b on the HLG, but I'll go look..
(12) QB132 / (6) QB312 with 600h's:
If you want to be competitive with a 600w HPS, you want to run closer to 480w at the wall.
Even maxed at 600w those setups should be fine. The QB132s because of their chip density and large surface area, and the QB312s because of their heatsinks. The only thing that is going to heat up the room is the lights and drivers. So if the lights are cool you won't have to worry about heat except for at the drivers. My lights run around 110°-115°f @142w per QB304 (4 active fans ontop of heatsinks), my drivers have areas that are closer 125°f if I remember correctly. Its just a matter of where the waste energy is being expelled at. With lower temps like that I don't have to exhaust like a champ I can just easily control it. I had extra E27 in my area this time and those suckers got to 185°f+ so I personally had to exhaust more than most.