AHS Class Action Lawsuit Settlement
There are/were a few people unhappy with AHS.
(edit)I don't know about whether the costs of the warentee are worth it. We got a new fridge, dishwasher, and microwave for $1,100 during a sale, but a water heater or a/c could become big money.
For the hassle, it doesn't seem worth it. Better to pay local contractors with good reputations and know it's done right.