Hey Ben, I have never used HPS/HID lights but I have researched the crap out of all of them. My opinion is based on what I have smoked as well as other friends non biased opinion you wont get the quantity the HID lights can give but were the LED's lack in quantity they make up for in quality. One of the factors of deciding what light is figuring out your grow space sq footage and than you take an LED's true watts (draw at wall) and devide the sq footage into the draw, if you can break 30 watts per sq ft your golden I personally like it closer to 40 but still tinkering. 7 years ago when I researched lights laws were a bit tougher, so I was nervous, I learned the HID's can be picked op on certain frequencies and I live close to an airport so I chose not to do it, also if you live up north its a bit easier just look for the house with less snow on it than ones around it. I thing the big seller is the cost and heat both are much lower and that works for me.  Good luck on your decision.