I did some research on LEPs (Light Emitting Plasmas) a while back and the light spectrum they produce is pretty impressive especially for vegetative but it lacks a bit in the red spectrum for flowering. The lights produce almost no heat and last like 3 times longer than HPS or MH. But they're still in development in my opinion.. gonna be a long time before anyone actually uses them. LEDs are going to be the future when costs are cut down but as other poster said CMH is the next best thing in terms of light spectrum.