I've used TravelGuard (the company that provides the DVCtravel insurance) a number of times, and they are excellent. I haven't used them for DVC stays, but have used them for other vacations. They're a large and very good company. On the two occasions when we had claims, they were very responsive. Their website is www.travelguard.com and be sure to call their toll-free number if you have any questions.
Before buying travel insurance, be sure you qualify and know what you're buying. Most travel insurance requires that you buy the insurance within 14 days of making your first covered purchase...so if you make lodging reservations and then wait a while to get your airfare, you could be out of luck on some portion of your coverage. It's a complex market and you really need to know about your insurance before you start making plans.
I second Jim's recommendation. We have had good luck with Travel Guard and have made a complicated claim that they came through with a very fair payment (it ended up involving DVC points but not in a conventional way, which was part of the complexity of the claim).