Personally, I just buy commercial MH and HPS bulbs from my local commercial lighting warehouse. It figures out to a whole lot less than going to the grow shop, and after shipping and delay in receiving it is equal or better than online.
Personally I don't see any difference in the results with name brand commercial bulbs and the fancy "Grow light" bulbs of the same wattage and type i.e. 600watt MH to 600 watt MH.
Threetrack,
I have never seen a 430 watt MH or HPS. If you're referring ot the numbers quoted in your post about the cost of running an HPS, the 430 watt was the total current drawn into the ballast NOT the output from the bulb or the rated size, which remains 4000 watt.
Great smoking.