Speaking from my experience as the service manager at an independent shop that works on many European brands -- Volvo's Platinum extended warranty seems to offer good coverage. Volvo uses a 3rd party to administer the warranty, but the Platinum contract does cover important items and actually pays.

If you decide to buy an extended warranty, read the entire contract THOROUGHLY and CAREFULLY. Look for coverage that is likely to be useful, and is not excluded by a bunch of conditions. Most 3rd party extended warranties I see cover next to nothing, and use vague language to provide the insurance company lots of ways to duck out of paying for repairs. Most extended warranties are a good way to throw away $3000-$4000 for nothing.