Is Untrasonic Electronic Pest Control, Effective?

tedgyz asks: "I have declared war on the pests in my house. I am tired of hearing the scurrying of mice and squirrels in my walls. Worse - I am tired of the nests littered with droppings buried in boxes in the attic. I have used standard traps, and although successful, it seems that new rodents or more than happy to replace the ones I've killed. Are ultrasonic deterrents effective?"

"I've searched the web, but I can only find marketing material from manufacturers and distributors. I'm looking for cold, hard facts.

1. Do ultrasonic deterrents really keep rodents out of your house?
2. What is the range?
3. Do they last, or do the rodents eventually return?
4. Are they truly innocuous to dogs and cats?
5. How do you measure success?"