Are Cree products really that much better than everyone else? It seems like they get a ridiculous amount of positive press on the forums. The only reason I don't use them is im In Canada and I haven't seen them in stores here.
Cree, Osram, Phillips. The bin #s are significant too. The problem is most consumer stuff is cheap epiwhatever LEDs. That situation is so bad that China mandated higher standards this year. I don't know if things have gotten better. But, it's a recognized problem.
In the post I linked to, I got 0.9g/w running 21 w/sq ft in a 9sq ft space for 20g/sq ft.
You 0.38g/w running 38w/sq ft in a 6 sq ft space for 10g/sq ft.
That's almost twice as much wattage for half as much yield.
But, if you didn't have reflectors that's a huge light loss. Being your first grow, skill could be a factor too.
If you're really into it, build a COB. I think the lightbulbs are better for single-plant, smaller spaces, etc. I like the bulbs because I can distribute light around the plant. I think sidelighting is one of the most productive things you can do. (That could be another factor between your results and mine.). But, you can make lower-power, lower-intensity COBs for more distributed, closer application than most(?) make. You'd get 30-40% more efficiency than the Cree bulbs. (I'm not into it that much, yet.).
I'm interested in LED strip lighting. I think something like SMD5630 ribbons would create interesting panels (hinged) that could be folded around a plant, or "winged" over the canopy.
Lots of fun things to do. But, yes, not all LEDs are made the same. (There are ribbons out there that wouldn't be good to use too.).