You got almost a gram/watt your first time growing? If that's true, stick with it I guess. Lol
It's not just a g/w that matters. It's also g/sq ft. I've grown under a Blackstar 130 (85w actual) UFO which is a rebranded Chinese epi-whatever light. I got 1g/w. But, I was only at 21w/sq ft. So, that's 21g/sq ft.
When I
added 38w of relatively efficient LED as sidelighting (which was 31w/sq ft), I got 1.2g/w and 38g/sq ft. The w/sq ft rose 33% and the yield rose 45%.
That was just one grow. And, I'm kind of mixing metaphors with light intensity. But, my point is, you need less w/sq ft with more efficient LED. He might have got 1g/w and the same g/sq ft with 30% less light if it were efficient.
But, I agree, 1g/w is good. I think it's more a testament of the grower's skill, the environment (spectrum being one factor). Nothing wrong with continuing to use that fixture. I still use my Blackstar.