What do you think?
Should I buy one?
Some time ago I measured the power factor on 5 or 6 different manufacturers of CFLs and found them all to be above 98%.Power factor correction is something needed for fluorescent lamps to stop them being inefficient.
This might explain it:
(The explanation with the horse is pretty good. At college it was explained as being like ordering a pint of beer. If it had a large head on it it was still a pint but was less real beer.)
From what I can remember both current and voltage follow a sine wave. If the two are together it's efficient. If not inefficient. A capacitor added can sort it out. A factory with a lot of motors might have a bank of capacitors to sort it out. In the home the only real thing is a fluorescent lamp and a capacitor in the fitting does the correction anyway.
So I'm not aware of anything else you might have in the home that would be particularly bad and if an appliance was, then the problem would be solved by adding a capacitor to the unit by the manufacturer anyway.
Yes you should, they do save energy.. How much though will depend on how much energy you are using...