I vegged under Procyons a few years ago and I'm inclined to agree with the statment about huge fan leaves and lush green with the LED's. I ran HID's for about 6 years and the plants just never looked as good and I don't think that was because I was screwing up
If you've ever spent any time in a serious jungle, like the Amazon, the top of the canopy is where the leaves look unhealthiest and below the canopy is where the plants are all lush and green. I think that's because the sun is very intense just like HID and there is a lot of spectrum that can't be used and it's hard on plants who are subject to the direct hit.
That being said there's no denying the numbers with HID. I used to consistently pull 7lb of 4X1000W HPS without co2 so I know that HID's perform and if you're a commercial grower that's all that matters along with low start up cost.
I also know that personally living on a HID grow was stressful. 240volts is lethal and you have to really know what you are doing with the wiring and it really doesn't mix well with water which is regularly present in any growing environment. The RF transmission from the ballasts can be picked up well off the property. The bulbs are so hot as to be a major fire hazzard and I don't know anyone who was a commercial grower who doesn't have a few scars from incidental bulb contact. 4x1000W HID lights need the equivalent cooling or venting to control the 14,000 BTU's of heat they are kicking off and that makes for a pretty impressive heat signature. You better learn to wake up when you hear the chopper
I'm glad those days are over and glad to be doing it for fun and with a license now.
Even if LED's don't perform watt for watt, they are close and I love em just for the safety and security of them and I really think that's one place where HID can't argue.......but someone's sure to try
One last point, for every 1000W of HID you need 300W of A/C (never met a commercial show that didn't run A/C and co2 but thats Canada so might be different elsewhere) so while we're comparing apples to apples even if it takes 1W of LED to produce the same as 1W of HID there is power savings on the cooling alone....just thought I'd fan the flames