PCBs have good light spread and heat dissipation allowing for passive cooling and even coverage. COBs generally need a thick heatsink and sometimes a PC fan for active cooling if you want to run em super hard. i think generally they’re similar in efficiency unless you really care about a couple percent (i don’t lol). they’re both kinda modular allowing lots of customization. the new quantum boards are using LM301B diodes which are maybe 8-10% more efficient than the LM561C diodes but it’s really not worth the money HLG charges for boards.
how big of a room or canopy do you think you’ll have?