I don't generally buy them, but I did for our range. My parents had problems with electronic cooktops so we bought the contract. It has more than paid for itself. It was set to expire today, so I renewed it for 3 years at a cost of $186/3 years a week or so ago. The oven started acting up, so we called for service. Without the contract the cost would have been over $200.
If you choose the right products, these contracts are OK.