Well? Specifically, do they repel the nasty buggers like cockroaches and ants?
I googled it a bit and found conflicting opinions but there seemed to be more agreement that they work better against rodents than insects. My mom swears by hers.
And although they claim to the contrary, will they drive our already neurotic dog over the edge?
Nope. Mother-in-law bought us those; we put 'em in, found ants crawling on 'em.
No cite, but I’ve read many times that they are mostly useless.
I’ve often imagined what the sales tactics must be on those things:
Salesman: Yep, this’ll keep the bugs away 24/7/365! Drives 'em crazy, it does! And it barely uses any electricity at all! That’s right, it’s almost free to operate! (flips switch) Hear that?
Customer: Uhm, no…
Saleman: See, it’s working!