I've been told by those in the business to look for an "exclusionary" warranty. That means if something is not specifically excluded in the contract it is covered. What you are getting is not actually a warranty, but an insurance policy. In other words you are betting (with your payment) that something will breakdown, the insurance company is betting it won't.
There are many who advocate taking the money for the policy and putting it in a bank account instead. That way if something happens you have the money at hand to deal with it. If nothing happens your money is still there and drawing interest, albeit not much in today's market.
If you do purchase a policy remember to follow the rules precisely if anything happens. Most have very specific claims procedures that have to be followed to a "T". Any deviation can be grounds to deny the claim.
Tom and Barb
'07 Winnebago Voyage 35L
Workhorse W22 chassis FMCA 219315