So a final update as the 2nd cut from my 1st LED harvest is now dry and in jars. Using ~950 W of MH LEDs (2x MarsII 900's, 1 x Reflector 48) over a 6' x 3' SCROG, I yielded a total of 515g or 18.4 ounces of dry bud. This does not include 4.5 ounces of popcorn that I chopped and dried and that will be used for edibles and more hash making.
18.4 + 4.5 ounces - 22.9 ounces = 642 g
642 g / 950W = 0.67 g / Watt
I have to say that I am very happy with this result for the first go-around. I have not grown or used my room in 2 years, and this was also my 1st time growing hydroponically or SCROGging, and know a few ways in which I can improve things for round #2. One of my limiting factors was genetics as the C99 grows like a pure sativa and isn't a big yielder, and that was 3/4 of my garden. The Cream Caramel on the other hand, shows the potential for really nice yields under these LED lights as she only took up 1/4 of my screen but yielded 6 ounces of primo rock hard bud from a single plant. By really dialling in my room and tweaking things, I am confident that I can get to .8 g/Watt or above for the next round.
All in all, I am very pleased with my MH LEDs, they more than paid from themselves on the first go. I invested about $1000 on the lights, but grew $4000+ worth of medicine (including hash and edibles). Growing under these lights increased the enjoyment factor immensely, I loved lower heat and noise in my room and spent much more time in there as a result. I am also very happy with the quality of the end product and the penetration of these lights. At 14-16" above the canopy, I still had big hard buds at or below the level of the screen which was very impressive considering how dense my screen was (too crowded in spots).
I'm a happy customer that will be buying another MarsII 900 (or equivalent wattage of Reflector series) for my next round. If anyone reading this is on the fence about these lights, take the plunge and you won't be disappointed.