I have been using them for about 2 years and they have provided great customer service. I also include them "at no cost" which involved me rolling it into my prices. I find that my clients and their realtors like the fact that I have this extra service and I haven't found it to be a negative. In the 2 years they have paid 2 claims. One was an electric water heater that stopped working between the time after the inspection and the clients move indate (about a month later). It was repaired and American Home Warranty reimbursed them. The second was a leaking dishwasher(it was strange that clients dishwasher was the same model as mine and we both got the same leak within 3 days of each other) about 60 days into the 90 warranty in which the client stated his other home warranty refused to pay for the repairs. AHW did reimbursed for the repair and the client called to thank me for offering the warranty.
I like the fact that AHW sends you an email with the clients claim, ask you some questions pertaining to the claim and then email you later with the end result.
So basically, I like it for my business model but it may not be for everybody.