Not true, I have personally done grows with equal wattages of cfl's and hps's. There is no comparison. I think in Weed World #62 or so, there is an extremely detailed side by side grow. Everything was equal, except one side was cfl's and the other was hid's. Hid lights penetrate much farther into the foliage than cfl's. There are many more reasons why hid lights are the best light source for growing these days.