Of the three I would go with Tutto.
Have you considered going to boardwalk, just outside of Epcot?
You have the options of Blue Zoo, Flying Fish and Kouzzina. Kouzzina is the best value IMO. Blue Zoo the best food.
Much like your parents, one of my biggest frustrations is paying good money for average food.
Le Celler is good, but on the equivalent of Bugaboo Creek (other say Outback, but it is slightly better then Outback), IMO. It was not as popular before the
DDP.
I think Tutto is good for the dining plan, but I would not pay for it out of pocket.
San Angel Inn has a great atmosphere but the food is below average in my opinion. They have bagged chips. When I am paying $24 for an below average entree in a Mexican restaurant I do not expect chips and salsa that were made in a factory in New York City ;-)
I have not had a good meal in the Coral Reef for 5 years. (I stopped going 2 years ago) It has become more about the "show" then the food.
As others have mentioned Morocco is good if you like that type of food, and I do.
They also have the belly dancer which is entertaining.
I also highly recommend Biergarten. I really like German food and we do not get it in Boston. I have been to Munich, Berlin and Salzburg and and the food is what you would expect from a tourist restaurant in these cities. (That is not a negative, just want to be up front with you.) Nothing is bad and the show if entertaining.
Unfortunately at the end of the day you will get 100 people with different opinions, some will even like San Angel Inn (I know it is hard to believe).
At then end you will need to make your best guess and hopefully you will be pleasantly surprised.