I would never say that spectrum is of negligible concern, Rick. Also, I can assure you, LED's, even the very, very low wattage ones, are far more expensive than a typical "shop-light", particularly if you figure in the amount of (usable) light available from each. My T5H (or HO, same thing) produces many times the same usable light (we are talking lumens here) as an LED of the same cost. I have tried them all, you name it, and have been greatly disappointed in my LED lights. Though they are supposed to last longer, in my experience, they do not. I had every single one of my 18" LED fixtures die at approximately 1 yr. Those were the largest I could find that were water-proof, something that I must have because of these lights positions.
I have never had a truly "powerful" LED simply because they require a fan to cool them. Apparently, they generate a lot of heat and must have internal fan-cooling. Thus, they can't be used in wet conditions. They are also extremely expensive compared to my T5H, six-tube fixtures.
