People don't go to Carnegie Mellon because the food is good.
I had a meeting at the beginning of the semester here, and the food was just kind of edible. We came in for the breakfast buffet, and the place was pretty empty at 8:30 AM. The made to order omelettes were OK but took forever. I waited 20 minutes with one person in front of me, which is kind of absurd. The bagels were low grade store quality, and the juices were all high-sugar choices. The fruit didn't look so good either. I'm really glad that I'm a graduate student who doesn't have to eat on campus.
I don't really know what the price is, but unless someone else is paying, I would skip the dining hall. The dining hall has plenty of seating, which is nice, though.