Heh, a 42-watt CFL doesn't put out 150 watts of light. Light isn't measured in watts. Watts is a measure of how much energy is being used, that's it, has nothing to do with light. A 400 watt HPS with a Hortilux bulb puts out around 50,000 lumens. To get that amount of light with 42-watt CFLs, you'd need like 20 of them, which would use twice as much power to get the same amount of light.

Since you need far less light during vegging than you do flowering, CFLs are fine (even great) for vegging, but they don't compare to HPS for flowering. That doesn't mean you can't flower with CFLs - you certainly can. It's just not very energy efficient in terms of how many lumens they generate compared to how much energy they eat.

All those "equivalent watts" ratings on CFL - ignore those. In the context of growing plants, that equivalent watts stuff is just marketing BS and should be ignored. All that is important to know about a CFL, when reading the packaging, is how many lumens it generates, the color temperature, and to a lesser degree how many watts (REAL watts) of energy it will consume.