I have a dual 250 watt metal halide system run off a standard ballast. I have never tried or actually seen an electronic one but here is what I have heard.
Electronic ballasts produce less heat and use less electricity then the magnetics, which is why they are so popular. However I have seen break downs for certain bulbs and the magnetic actually produces a brighter more intense light then the electronic. Now this is probably totally unnoticeable to anyone that cant destinguish the diferance of a few lumins.
If you have the extra money I would say go with the electronic it will save you some money in the long run with reduced utility bills.
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Adam
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