It is difficult to trust any site that is trying to sell new product. When I looked into it about five years ago, LED`s were slightly less efficient (lumins / watt) then florescent. I am sure that as technology progresses, the LED have become more efficient then florescent. The claim that they are twice as efficient seems doubtful to me, but maybe.
I generally laugh at people who quote Wikipedia, but the numbers on Wikipedia look believable to me.
Luminous efficacy - Wikipedia, the free encyclopedia
For a florescent
light, the ballast has a large effect on the efficiency. With an electronic ballast, florescent has an efficiency of 80 to 100 lm/W vs. 4.5 to 150 lm/W for a raw LED. With a theoretical efficiency of 300 lm/W, (44%).
LED's have many other advantages as well. Bulb life is hard to beat, cold temperature performance, compact form, fits in existing fixtures, cheep, low voltage performance, arguably better light quality, .... LED's are obviously the future.
The only point I was trying to make is that it may not yet make sense from a cost vs benefit point of view to change from florescent to LED.