Sooo I've been following the Vero 29/CXB3590 discussions around here for awhile now, planning my own LED light, and while researching manufacturers I found Citizen, and the CLU048-1818C4 in particular. It's their latest generation, and I focused on comparing the 4000k 80 CRI version because thats what I found in stock online. Here's the datasheet: http://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/COB_5/CLU048-1818C4_P3371_1115.pdf And the fun part: They don't bin, just give minimum and typical figures like Bridgelux, but at the 1620ma test current, 52V and Tj=85C, the COB makes 12249 lumens typical, which is 145 lm/w. Isn't that nearly the same as CXB3590 CD performance? Looking more at the data sheets and numbers given by Bridgelux and Citizen, the Vero 29 at Tc=25C makes 10,693 lumens typical using 79.8W, vs the CLU048 at 25C making 13,392 using ~87.5W. 134 vs 153 lm/w by my math. Its hard to tell how well the CLU048 scales down with current since all I can do is squint and guess at their low resolution charts, but it looks like it doesnt gain as much advantage moving down in current as the Bridgelux, but its overall efficiency is so much higher it doesn't matter. A HLG-120H-C700B should be good for 4 COBs at ~36W each, hopefully making well over 150 lm/w. Good stuff.