Absolutely beneficial. When I grew with CFL's, I grew in an area 2ft x 4ft x 4ft. I had 12, 23 watt bulbs hanging from the top, and had 4, 4 ft. florescent lights on the back wall. They made a big difference from my first grow with out the back lights.
![DSCN0112.jpg](/data/attachments/2086/2086233-6d802955d128eeb569db7a22fc955038.jpg)
This is how I have my tent set up currently, but when I get the chance would like to add some more lights.