Same ballast, the same energy goes into the bulb resulting in the same light and heat output because the the little bulb in it and the metal valor in it is the same.
Why does the sodium valor or mercury valor lights are so cheap? It is because they are not market for the reef tank. The technology is the same just the composition of the valor is different.
Normal T5 bulbs are very inexpensive (less than 1 dollar per bulb) Same as other household florescent light bulbs. The aquarium industry did not invent the technology for reef tank, these manufactures just adapted the technology for reef tank, namely adjust the composition of the chemicals to produce the correct spectrum for corals. Once this is done, people can easily copy them. I certainly use them without problem. If you are willing to pay 5 times more for the same bulb, be my guest.