I've been with warranty direct nearly 3 years since my 1 year nissan used car warranty ran out, and the yearly cost is still less than nissan wanted to charge me to extend it after that first year.
I can't say i've had to claim yet, the only experince was a local stealers telling me i needed to pay over£400 for new shock absorbers, so i phoned up warranty direct to arrange it, they were find with it, just needed the stealers to fax over a technical work sheet, and then then informers me that the garage was just trying to rip me off and it was just the gaiters around the springs that were perishing. Got a few other opinions and was told i needed to not bother doing anything. So they just saved me getting ripped off.(or themselves....)
They do have good customer service, always polite on the phone, personal email replys, happy to send any info you need, and can usually be brought down in price, or get a few months free even!So no practical experiance, but happy to keep renewing whilst price is ok.