We went for the Sunday Brunch, which was just ok.
It's about $30/person for the brunch, which I think is fair since it is a buffet and the spread is pretty impressive. They have everything from a doughnut machine, to omelets, to lunch food and desserts.
BUT, the food just tastes mediocre, so I personally would rather eat less food, that tastes much better.
The building itself is interesting, so that's really the only reason I would recommend going. The main seating area is very...GRAND haha hence the name, and the side railhouse seating is also really nice and has large windows for a nice view of Pittsburgh.