300W Grow King LED -vs- 400W HPS

I have been refining my technique in my small 4x4 closet grow using a 150W HPS and have been getting good results for using a small lamp. I am a simple organic soil and seed SCROG grower who would be happy if I could get 1oz per month of final product. My biggest difficulty is heat. I can only grow 7-8 months out the year and barely squeeze 3 grow a year in before it get too hot in May and I have to shut down. I ready to start back up here again and am ready to upgrade to a larger lamp with hopes of doubling my harvest so I will never have to buy my personal supply again.

At a distant hydro shop I have the choice of a 400-600W SunAgro HPS lamp and a newer technology 300W Grow King LED. The shop owner, who is a medical grower, recently switched over to the LED and swears by it. I've seen and tried his LED product and was fairly impressed. While the LED light is about twice the cost of the HPS, he says by the time you figure in the cooling tubes, hoods, larger exaust fans, ect you need for the HPS, the cost isn't really that much different, maybe 20-30% more.

One of my biggest challanges is I can't grow during summer as my closet would push 100 with my little 150 lamp and the plants suffered so much it wasn't worth the effort and cost to grow during summer. With a 400W, summer grow would definately be out of the question and would probally even cut my grow window down another month or so. AC isn't an option for me.

In the effort to keep my temps down and possible extend my grow season, are these Grow King LED a worthwhile subsitute for a 400W HPS? I know what a HPS light can do and am impressed with the final product, I just want to lower my temps, extend my grow season AND get some decent volume and dense final product.

Peace,
Ala