It really isn't very feasible comparing watt to watt for HID vs LED; it really is an apples to oranges comparison. The reason is that a lot of energy is wasted as heat and other non-usable spectrum in an HID, while very little is wasted in an LED unit, as the spectrums are more finely tuned into what 'they' call PAR (photosynthetically active radiation). Now, there's always going to be a debate about what the optimal PAR is for MMJ, but what can't really be argued is that LED is the only lighting technology out right now that can be fine-tuned to the optimal PAR (if it is ever found) and not waste a lot of energy as heat at the same time (except maybe plasma, but this technology is primarily touted as being the closest to sunlight than anything else). Another thing you must factor in a watt to watt comparison with HID and LED is the energy spent on heat management, as those fans still consume energy. I do not have any sort of heat management, as I don't need it. This can't be said for HID.
So, in my educated opinion, I'd have to say that LEDs will always win in overall energy consumption. But don't make the mistake of trying to compare watts to watts when speaking strictly of light output, as this just isn't a practical question.
I got mine for $699, but they have raised the prices since then. I'd still buy it in a heartbeat though. Actually, I am going to buy another for my next grow.
