2 105 cfl lights will give you about 12,000 lumens, a 150w hps is about 16,000 lumen. The exact lumens output varies slightly depending on the light. So technically the hps is going to be better. However hps lights are very hot and quite expensive. Cfl lights are smaller, cheaper and cooler to operate. I changed from a hps light to cfls and although the plants are getting a bit less optimal light they are doing very well under cfl lighting. Another thing i noticed is that cfl lights are natural to the unsuspecting eye - in other words if you have a street light (hps) in your house people may start talking. I use cfls and can leave the grow room door open and no one is wiser, they are not as obvious as a HPS. good luck