600w lights,indoors.

im lookin to buy some 600w hps, What is the difference between the more expensive 600w, an the less expensive. are you paying for a higher yeild or the name brand?????

Your paying for a better light spectrum.

ok but what about the whole system what if u get the good 600w bulb with a less expensize ballaste an hud does that matter

Yes it does. Some are made cheaper with cheap parts that are important to get the bulb to strike fast and longevity of bulb and to brighten the bulb. The one I prefer is Lumatek with the switchable output. E bay cheapest price around, look for free shipping.