I think the key to being happy with Disney Dining is to go into it expecting everything (food, service, theming, etc.) to be merely "pretty good." Because pretty good food with pretty good service is still a pretty good meal, right? And "pretty good" is a standard that Disney can nearly always beat. (Whereas if you expect everything to be amazing all the time, you'll be disappointed.) In fact, I've never had a dining experience at Disney that I wouldn't be willing to repeat; they've all at least met and almost all exceeded the "pretty good" standard.
That said, we have relatively high standards for what we consider to be great, and we were blown away by the quality of the food at Mama Melrose and at Akershus dinner, relative to what we had expected.