looking at the big picture, I think you'll be better off buying an actual grow light (mh/hps) at that price. For $200, you can easily get a good deal at HTG or someplace like that. I know I got a 400w hps with a mh conversion bulb for about 200. I'd say the only benefit from the cfl light is the amount of heat it gives off or lack thereof.
In comparison, the 315w cfl gives off 17,000 lumens while a 150w hps gives off 16,000 (and around $70). So in reality, you wouldn't be saving on electricity. I currently have 4 plants under a 400w mh and they're happy if that helps you put things in retrospect. Just my two cents.
