Ok yes and no.
For me- it's no. I use a 600w HPS from start to finish. When I want to flower I change the timer to 12 hours of light a day to trigger a season reaction in the plant that tells it to flower.
For a lot of other people, they use CFL for vegging but if they were to try and CFL to flower it would end in disappointing results because it simply would not be strong enough.
People get really split by this debate but i'm on the side of never using CFL because they are piss weak. They use less energy but i'm not looking to save some loose change in my pocket- i'm trying to grow the fattest healthiest plants with the best equipment. For all those people who go on about the CFL's light spectrum being better- you still can't beat a HID lamp- just use a MH instead of a HPS.
Anyway like I said- HPS start to finish is better than cfl then hps