I will pop in my two cents for what its worth.
I purchased some just like the screw in type on Ebay. 168 leds per bulb. I used 5 mixed red/blue and4 far reds. It was on some Northern Lights. First plant, I drowned, starved, overfed, and still after topping a few times, had about 1/2 to 3/4 ounce(no scale at the time) of some very respectable stuff. On the second plant, I was a bit smarter, proper drainage and proper nutes. It yielded 3/4 ounce of VERY potent smoke. Nuggs were respectable, curing to the diameter of a quarter being 1-3 inches long. There was trichromes covering buds and 50% surface of leaves as well. (hey! it was my first grow...)
I supplemented with 2-3 cfl screw ins (Thx Knowm) and 2 18" t5's. Grand total of maybe 160 watts.
My benefits were no smell at all outside grow cabinet, NO HEAT! buds were touching most of the time due to height restrictions. And I had GROWERS sitting next to the monolithic cabinet I cobbled to gether in a relatively nice chill room. NO ONE KNEW! (I didnt want to embarass myself until I was sure) After I showed my end result to them, they were mildly impressed.(They all use 1k's)
My advice is as follows.
If you use them, use the screw in style(Like on ebay), or a higher grade,i.e. Procyon, Lightblaze etc.
Be sure to have ample blue spectrum. I will be using more CFLs next time.
If using a far red spectrum, then MAKE SURE to give it plenty of blue spectrum as well.
Do your research. As I said, I was using 9 total and with 20 bux worth of cfls from Home Depot. This brought about a substantial return in my opinion. And I enjoyed it immensely.
Before the flames start, remember, this was my first grow, and I only had 1 plant that I had to force bloom to coincide with a move. I will post more on my next grow.