I USE 150 WATT HPS AT TIMES. I used to grow only one plant at a time. Take my word for it.
Doesn't matter what anyone here is saying... this all depends.
The CFL's can each get within an inch of multiple budsites (you can have 1 at the top and the other 4 close on each side). The 150watt HPS can only get close to one bud site and the rest go to hell. The HPS is worth it ONLY if you are able to have it close to all the bud sites.
If you want the best and more abundant harvest, supercrop or top or LST the plant..... get it so that the bud sites form a canopy rather than a single cola. If you try to use the HPS on a regularly shaped plant you have to keep it atleast 6 inches from the main cola... and anything more than 18 inches away is nearly non-existant. You will get 2x the yield but if you supercrop or top it may take another 2 weeks to vegetate the plant.
If you want your buds sooner, and want a large cola with some smaller (but still decent) buds... use the CFL's and grow it regular. You can get the cfl's very close to the bud sites (if they are 2 inches away from the bud sites, they are getting more light than they would 6 inches from the HPS). However, you will only be able to have a couple of good bud sites, the others will suffer.
The HPS can cover a 2x2ft area decently, if you keep it 6-12 inches away from the top of the plants. Your BEST option is to grow the plant in a 5 gallon bucket and LST it until it's ready (or top/supercrop it and wait another week or 2 since the growth will be slower). Then use the HPS to flower it.
If you use the CFL's you'll probably get about 3 ounces dry
If you use the HPS without supercropping/topping/LSTing the plant you'll probably get about 2 ounces dry
If you use the HPS and supercrop/top/LST the plant you'll probably get about 5 ounces dry.
My first plant I grew in 3 gallons and flowered close under the Hps without trimming and got almost 2 ounces dry. The clones, when topped so that they formed a canopy gave nearly 4 ounces dry(one plant).