LED lights in grow box

Has anyone tried the LED's and gotten good results? If in a small spot wouldn't it be easier to control the heat with LED's, which have little to none. I am reading about the UFO, I don't believe everything but it does sound good except the price but the energy draw is less and they last for a lifetime if cared for, at least my life time.

I understand that the older guys are not going to try the LED's, they are stuck in there ways but any comments as long as there real will help.
Thanks

i've heard great things about LED's, but its still pretty new to everyone no one has that much experience with it. I'd say buy it, try it, tell us.