I have used cob fixture and now I am using project 342 from Italian shop .In my opinion cob fixture work very well but board can be an even better choice .My measurement (and measurements from many other member) showed me board are more efficient, with better uniform coverage.I do not ever tried a quantum board from hlg, but compared my result (and result from seller) with led gardener. My board seems to be more efficient and more uniform.Again,never tried a qb so I can be wrong, but result should be true since my bord has more diode and larger pcb.Another big plus is I do not need heatsink .At 100watt is slightly warm, at 130 watt is around 50/55 ° C , so around same temperature of a qb with heatsink at same wattage.