i have never run a 600w alone, i have 850w in the first , can get good coverage and penatration on 15 4ft plants in there yielding 3oz - 3.5oz dry if cheese, in the other is 1000w a 600+400w and i get 20 5ftish plants in there yeilding 3.5 -4oz dry. you are never gonna get that coverage or penatration with those panels, not ever, you would need to many and they cost to much, ok you can control your climate , no heat issues, infact you will prob need to send heat in , but the fact remains despite what manufactures say they are not powerful enough, i agree for a personal yeild in a closet , and you dont mind the high first cost outlay per panel then why not , led's are not new , i dont by into there is more development to come either, they can grow small short plants than can cluster some nice nuggets althought 65% of this is down to plant genes, i know you no this too, my friend, i wish they had the power,penatration and coverage,because the saving on electric and not having to run fans is a major factor in this, but if we are talking yeild versus yeild, its not a fair comparison because with a hid light you can grow larger plants and im stating the obvious to say that larger plants yeild more , i will try to find out where they are buying thier panels from .......