N.B.
I have had American Home Shield for about four months now. I have called them out once. The response time was fast and the contractor was professional and arrived on time.
The thing you have to realize with this service is that they will not replace your appliances unless they are completely inoperable. I was unaware of this at the time I purchased the warranty.
My hot water heater (7 years old and in my attic) was making noises and I knew that several of my neighbors have had theirs burst and cause water damage in their home, so I called AHS, who sent a contractor out.
When the contractor arrived, he went into the attic, looked at it, said to call back if it actually starts leaking and charged me the $55 service call.
My thinking was to catch it before it caused damage but they do not operate that way, so I basically wasted $55.
This is my only expoerience with them thus far. I guess it is a good service, if you have aging A/C units, or something else with a sizeable replacement cost.