They are not much better than Dental Insurance
I have on occasion purchased an extended warranty. It has always been from a Cerified dealer. This way you can take it to any certified dealer. Mine was from GM services. I viewed it as a insurance policy on the big ticket items(rear end, trans, engine, ECU). The policy had road side/vacation provisions( towing and rental) and was good at any GM dealer or approved service center. It was a 3yr $1200 insurance package. My thought was that if I pull the guts out of a tranny on vacation it could cost in excess of 4k (Towing, rental, service, etc.., loss of time trying to resolve the issue). $400/ year was worth it for me. There are alot of policies out there. Take the advice above, talk to your local dealer in the service dept and see which one they have dealt with to get pro's and con's. Everyone has an opinion on insurance policy's so the final is what you think of spending your money on. The only real advice I will give you is READ the policy, ask alot of questions, and never buy a policy that doesn't pay the service center directly. If your trying to buy a policy for window motors and alternators---Save the money in your own bank. You'll get farther.