When I'm in downtown Pittsburgh this is my preferred place to park. For what I do downtown it is the most centralized parking garage. Parking rate is fair but better during the evening hours and weekends. Dependent on what entrance you use to enter the garage will dictate which lobby you will use. If you enter on Penn Ave you are in the Red portion of the garage. If you enter on 11th St you are in the blue portion of the garage. It is true, it is kind of divided in two as the train tracks run right through it, but it is all connected.
The attendants that work the lobby areas that are to assist you for payment are less than enthusiastic, but hey, use the self service kiosks. What amuses me are the elevators, more specific is the voice that lets you know you are "Goooing Doooown."
As for the bus station portion, I have never taken the bus, but the facilities look rather decent. Small store, vending and video games. Your generic metal benches for seating.