Bests & Worsts Reviews from Amazon

I have a 3000 sft home, 2 story, built in 97. I bot 4 of these and put one closest to my main electrical box and the other 3 at the farthest points in my home. This month's bill dropped $30 from $95 to $65, a 30% savings, and my kwh's dropped 20%. It worked. I couldn't believe it. I've tried everything to cut my electric bill, this works best, cheap, easy, transparent. I don't know what the naysayers are doing wrong...I read here that you need a minimum of 2, you need to place them around the house and one nearest the main. I wish the naysayers would say how many units they tried and how they laid them out, but they don't. Are the naysayers living in old homes with older wiring? Did they only buy one and not two or more? Did they not read the messages about placement? They never say. I figured they were cheap enough I could afford the risk. It was a no brainer for me, instant payback and hopefully it just keeps saving me money.