Ok. I have never used led. And I never debated its validity. But I do know from experienced growers that they lack penetration compared to my HPS.
And in my set up and house they would cause me to need lights on heat in my growroom. Which is really expensive with propane heat out in the woods. So I added LEC.
It's the 315 LEC that isn't powerful to penetrate my already HPS bushy plants. I am going to try rotating them all evenly under both kinds of lamps to compensate.
But the LEC has increased plant health and potency from the better spectrum and uv so it stays.
I have grown with both and HPS has some self inflicting issues.
LEC is great and efficient enough to talk about but it lacks coverage area with a 315W only covering 2.5x2.5, so that means more lights and more bulbs.
True, HPS is a good light for what it is, but the reason you need "penetration" is because of the spectrum itself! It's a catch 22 with the light. Now if you take a look at my signature or my side by side thread you will see that the LEDs have not stretched nearly as much but also stay much lower in the Scrog. So it doesn't required penetration in the first place.
Also in my signature I demonstrate that penetration doesn't go past the first leaves anyways due to the light being absorbed.
The cobs don't have a penetration problem then have a cost problem. The old diodes have A lack of coverage just like the HPS lights do, it's not even and can't get to that state without multiple light sources which is why COBS will be better for a long time till the tech evolves in some way.