Food is best at Brown Derby. As a signature, it should be.
Best theming is Prime Time Cafe. 1 of the best themed restaurants anywhere on property, with a fun wait staff. Food is actually solid comfort food.
Most relaxing is actually Sci Fi: cool, dark, and quiet as everyone quietly watches the movie screen. (food rather generic applebees quality)
Hollywood and Vine is the best (and only) buffet on the list!
In a lot of ways, I find DHS actually has the best TS dining of any park, with the good theming combined with a few solid quality options.