If it sounds too good to be true, it usually is.
There's a ton of shit "developed by NASA" because NASA can afford to do a lot of research. Just because it was developed by them doesn't mean shit.

I'm not taking sides, but Block sounds like he knows his shit. Especially if he's a lighting engineer. He has nothing to gain from proving his point.
The Grim Reefer Reviewed by The Grim Reefer on . About those LED lights I was reading that in order to equal one decent HID light, you need a panel of like 52 LED grow bars. One LED grow bar goes for $150, so that's $7800 vs like $300 for the HID. You do get greater bulb life, but 52 led bars, with three light clusters per bar, is going to take up quite a lot of space, so there's absolutely no real advantage. So don't waste your money on LEDs. Rating: 5