Pros: I think the amount of time to make your home bug free varies.
Cons: Be patient - does work, may take longer than instructions predict.
I was amazed that a couple of reviews said that this product didn't work. Like another rater upthread said, I too have had mine for over 7 years, and it is =still= working.
To understand my infestation, think southern California, think older (50's built) wood and brick apartment building, with minimum upkeep by manager. I once told him that I had termites - evidence before I saw many in my house, was the small little black dots of wood that fell in my bathtub - landlord gave me a can of ant and roach spray! Whatever!
So, once upon a time, I had termites, roaches, spiders and ants. In fact, every time I turned on my oven, a small hoard of nearly white roaches would swarm out - they obviously lived around the pilot light and had mutated from the sulpher fumes.
Long story short, my Mom had one of these things, and although she lives in a much different climate, had spiders, the Riddex worked for her and they seemed to have gotten rid of the spiders.
So I bought one. It didn't happen overnight, let alone 2-4 weeks, but, after a few months, I finally realized that I hadn't seen a roach in a while, even when I turned on my oven.
From my understanding, it can only do so much, as it is restricted to the pulsing of the electrical system. And some walls and areas of the house, don't have electrical wiring in them, so any pests in those areas, might take longer to be affected, until they might move to an area that is directly effected by the pulsing.
Anyway, haven't seen a roach in my house for 6+ years; the termite problem is pretty much history; and, ants no longer find their way in. I occasionally see a spider, but more often when I'm moving furniture to vaccuum, I find little dessicated spider bodies.
To sum up: For me, major infestations of assorted pests, got Riddex, no more.
This thing does work - I just think the notion of it working in a couple, or a few weeks, is just too optomistic.