My uncle has always been a MH/HPS guy. My brother always tried to outdo him with various brands of LEDs and nothing ever compared to my uncles crops. My brother switched over eventually.
Myself, I use a 600 watt LED light to supplement the last four weeks under the 600 watt HPS (actually the last two weeks of flower I use a MH to really crank out the THC) with good results. I’m also in a 3x3 tent. That is what Ed Rosenthal recommends in his grow book.