Tiffins and Flying Fish! I can honestly say everyone in our family has enjoyed every menu item we've tried at either Tiffins and at Flying Fish -- the quality of food and service seems to be consistent at these two restaurants. And Tiffins customer service has been such fun, with the gifts of art prints and fresh made candies, along with personal visits to our table by the restaurant manager.
We do also like Jiko, but find the dishes there can be hit or miss -- some are fantastic, sometimes one or two menu items will be disappointing.
As an aside...
I know it is only a 'one credit' sit down, but the Jungle Navigation Co. Ltd Skipper Canteen is a hidden gem of a restaurant located inside the MK. The service can be very entertaining, the menu is brilliant (definitely unique), and their food quality in our experience has been exceptionally good.