I was just at Disney World a few weeks ago. I ate the German, Japanese, and Canadian restaurants. I found the quality of all of them to be very good. I was happy with most of the food I tried at EPCOT and the other 3 parks in WDW.
I was on the Diseny Dining plan which was a good value. For $35 a day you get one quick service meal (entree, soft drink, and dessert), one snack (ice cream from one of the carts, popcorn, etc...), and one table service meal (appetizer, entree, soft drink, and dessert).
The bill for my wife and I at the steak house in "Canada", Le Cellier, would have been about $100 if we had just paid on our own.