it all depends... it takesa very skilled grower to achieve equal / better results under fluoros

see, HID lights, (hps in particular) put out lots more light per watt than fluoros... BUT check the spectral distribution on them, most of them suck, even the good ones put out the vast majority of thier light in the spectral range that is useless to plants... so you can have balls out lumens, but if they aren't in the right place then they are being wasted... HID lights waste alot of light

fluoros can be bought in a variety of spectrums, and can be matched up fully to growing so that ALL the light output from them is being used by the plant. fluoros are available in color spectrums that are far superior to HID lights. period. the problem with fluoros is that they are so much weaker than HID lights that the tiny amount of light from the HID that the plant can use STILL overpowers most fluoro set ups.

i have seen many very very respectable all fluoro grows, but if all the factors in the equation were the same, done side by side with clones, you would end up spending just as much if not more on initial lighting set up to get the fancy fluoro's in the amount you would need to compete with the HID.