ON AVERAGE, you will lose considerably in buying an after market warranty. They are profitable to those issuing the policy, and those paid to sell them (the dealer gets a commission for selling you an extended policy - both automtive and RV). Otherwise, they wouldn't be available - and you wouldn't be asked to buy one at closing.
What you are really buying is (partially) prepaid repairs, NOT a warranty. The deductible and claims paperwork are designed to discourage you from multiple small claims. Are you likely to spend the amount of your premium in covered repairs during the life of the policy?
Note that my opinion on "extended warranties" is very different from loss insurance if you have financed your camper. Given the amount typically financed, most of us would have difficulty paying off the loan in full in the event of loss of the trailer. If you view, as I do, that insurance is supposed to prevent financial disaster when the bumps of life occur, then loss insurance makes a lot of sense. Repairs and maintenance are a cost of ownership, should be planned for, and should not cause a financial disaster.
just my opinions