I wish I could find the link but there is a grow journal on RIU where a guy did a side by side comparison of 1000w hps, flouro tubes, and cfls he was only use 3 26w cfl.... even though he only used 78w of cfl and the wrong color spectrum to boot, but in any event he did a total break down of cost to run vs production and the cfls came out on top by a wide margin...... after his experiment he decided to build a 1000w cfl grow box ......... that should tell you something .... they can and do work just take a look around the site you will see for yourself
and i dont see where people get the idea that cfls arent so efficent...yea they might not do thier best in a big room,but people that have limited space or are on a budget will use cfls or floros as an alternative to a hps,and im not downing hps's at all,i even plan on getting one when i get a bigger growing space,but my point is that cfls are still great for people growing in a small space or a limited budget,or even if your growing just a few plants,what do you think they used before hps or mh were even invented?...try that
if you read the thread you would know that he needs lighting for a 6x6 room with 12 plants, how could you do that efficiently with cfls