I bought an extended warranty to cover the time that my truck is under payments - bad feeling to have to pay for repairs when you don't actually own the truck yet! BUT... I haggled over the extended warranty price, and ended up paying less than HALF what the dealer originally said it would cost. This was a warranty from the dealer -- I don't trust that mail stuff I get about buying extra warranty protection from a company I have never heard of and having to make payment arrangements with independent garages, or with the hope of a reimbursement sometime in the future.
Another dealer (with a questionable reputation) was offering a 10 year warranty - as long as ALL work, repair and maintenance, was done by their own shop. This included following their maintenance schedule, which had a lot of extra stuff beyond what the owner's manual said was necessary.
As with all things regarding car dealers, research everything, and don't sign until you are okay with everything.