here's my diatribe: always keep in mind LUMENS, and how close you can get them to the plants, and for efficiency, just always remember, and calculate LUMENS PER WATT

then you know where you're at lots of impressive grows done with cfl's including envirolights

you get more efficiency with HPS, but there's plenty of reasons why that might not work in your case

the thing that we need to know is your setup; room? closet?