I think that DVC owners who are spoiled by spacious, high quality DVC resort accommodations would enjoy staying at Marriott Vacation Club International (MVCI) resorts, especially if they can get a decent discount. But I don't think you'll have much success if you just ask for an II discount when checking in -- although you might have a chance when you make reservations. Just don't think that you're automatically entitled to an II discount.
I'm an MVCI owner, DVC owner, and II member (because I own at an II-affiliated MVCI resort, and I pay for II membership). When booking at MVCI resorts for cash, I always try to get discounts. I ask for the MVCI owner discount (25%) and Visa discount (10%). The MVCI and Visa discounts are additive, allowing a 35% discount. If I can't get those, I ask for an II member discount (20%, I think) or
AAA discount (10%).
The problem is that Marriott sees the discounts as a way to fill empty rooms, not as a benefit to encourage MVCI ownership or II membership. So you're unlikely to get a discount during peak periods. Also, the discount is off the full, rack rate. So you can often do better with a promotional rate.
A couple of years ago, when I made cash reservations at Marriott's Manor Club (Williamsburg), the reservationist could not give me the MVCI discount, but she could give me the II discount. That seemed strange, but she could only do what her computer screen allowed. More recently, when I wanted to stay at Marriott's Desert Springs, the reservationist couldn't offer me any discount rate -- just the full $500 per night rack rate. But the same reservationist was able to give me a great rate at Marriott's Newport Coast Villas for the same weekend -- 35% off the off-season rate. That's because Spring is peak season in Palm Desert, but a lower demand time in Newport Beach. And earlier this year, I got a terrific promotional rate through
http://www.marriott.com for Marriott's Cypress Harbour in Orlando -- much better than the owner+Visa discount rate (and, no, it didn't involve a timeshare tour).
Bottom line: You're not automatically entitled to an II discount, but you can get decent rates at great MVCI resorts when Marriott is trying to fill empty rooms. It won't hurt to ask for an II discount on the basis of your DVC membership, even though technically it's DVC, not you as a DVC owner, who is the II member.
Good luck!