We crunched the numbers for our family of 5 (3 hungry teens, 2 like their food familiar).
Onsite, we'd get a week in 2 value hotel rooms, 2 baths, 2 TVs, 2 restaurant meals/1 snack daily, 2 days of (longer) MYW tix, free parking, go offsite for most of our days (other parks & water parks), pay for a lot of additional food at restaurant prices.
Offsite, we'd get a week in a deluxe 2BR timeshare resort condo w/2 baths, jacuzzi & a full kitchen/laundry, 3 TVs, 1 restaurant meal daily, 2 days of (longer) MYW tix, pay for parking, stay offsite for most of our days, stock up on a lot of additional food at grocery store prices.
End result? They'd cost the same for us!

So...
Our family prefers to eat restaurant food once a day, not more. We prefer the comforts of a spacious condo w/ room for all the teenagers to spread out. Our teens prefer the laid-back, fun, resort atmosphere of nicer timeshare resorts to the bustle at Disney value hotels and even the moderates, if we were to pay more for them.
As a family, no, we're not enticed.
Now... perhaps... if it were just DH and me... that'd be another story...
We'd basically only eat what's on the dining plan anyway and we'd enjoy trying some of the priciest restaurants that we haven't, so far. I'd miss the jacuzzi and the living room space but we'd do it for the dining.
