As far as up front incentives, the $200 offer is the best I've heard of.
You'll get notified of any discount offers to Disney Visa holders like the recent kids free and free dining promotions. You usually get first crack at those before they become available to the general public. If you book a package using your Disney Visa you get no interest for 6 months. You get $1 reward for every $100 you spend. They occasionally send out offers for 3 or 5 times reward points with certain criteria that must be met. Also you get free 5X7 character M&G photos at Epcot.
To me, it's worth it to get the card for the early access to the discount offers and to fund my trip w/ 6 months no interest. If they are ok with waiting for my money, I'm ok w/ letting them wait.
But for every day use, unless you have a trip coming up and they are offering the 3 or 5 times rewards, I think you're really better off using a cash back incentive card since it doesn't lock you in to spending the money with Disney.