Being a sales rep, I am in vegas at the Mandalay Bay convention center more than I would like. The food court is close and easily accessible. The lines get long but the servers are fast and efficient so you don't really have to wait long.
Bonanno's is a go to for me. I tried the rest of the places, but the pizza in the food court is the best. It's a pretty authentic NY slice and the Stromboli is great too.
One slice and a side salad is $10 but enough food for lunch. Two slices would be too much.
Trade show people- give this place a shot. It's better than the other options!
Hotel guests- there are better options away from the convention center in the hotel.