Even though I run HPS and I have no intention of changing any time soon, the answer is clear that LED produces much much more grams per watt of power.
What LED does not have is the penetrating power of HPS as it is further from being a point source so the lumens are spread over a larger area.
If you grow in the classic top-down manner and adopt the techniques for growing with LED that mitigate this, like stripping upper fan leaves and so on then LED is a clear winner, less heat, more light, less power.
I run vertically with lights central to an outer core of plants and I need lights which take up the smallest space in the middle of them. As such LED is problematic for me and I will be investigating a LOT more before I consider changing.
On top of this, LED tech is a rapidly changing field right now, HPS is mature and does not change as quickly. The best HPS light from 2 years ago is still pretty much the best HPS light. Not so with LED lights. There are bright minds at work designing new fittings with new LEDs in them, some are here on the site, and these are coming out relatively often. This is something to consider.
What is not so certain is grams per square foot, or grams per week per square foot. When using these other methods of determining efficiency it is not so clear cut.
But within the limits of this thread's discussion, being grams per watt, there is no doubt. LED is roughly twice as efficient as HPS to produce 1 gram of dried bud.
EDIT : I am unfamiliar with CMH so I won't talk about them