There is no reason to ever buy HID again.
Plasma has a better spectrum, a longer life, and pays for itself quickly. Plasma provides full spectrum photosynthetic active radiation (PAR); promotes faster budding, flowering, and fruiting; increases the quality of fruit; and shortens the overall growth cycle for most species of plants. In animals, it has been observed to increase health, promote higher activity levels, and better skin.
Plasma is a game changer.
Below you can find some more detailed information in graph form explaining the spectrum, lifetime, and return on investment in a little more detail.
LEP offers professionals and hobbyists alike, the first real chance for artificial sunlight. The spectrum extends continuously from UV to IR.
The fixture will last an average of 50,000 hours or over 7 years at 18 hours a day. Depending on your setup, you might be changing your current bulbs 3-7 times in that period.
During the special Kickstarter promotion, the plasma fixtures will pay for themselves within 2 years of purchase. In the example above, the Sunstream LEP fixture operates at 265 Watts using about half as much energy as traditional 450 Watt fixtures.