Pittsburgh's airport is a lot like the city itself - people aren't all "OMG, we need to go to Pittsburgh next year instead of Paris" but once you're there, you realize "hey, this is pretty nice, I kind of like it here".
It's a surprisingly large airport for a smaller market and has a train that you have to take from the gates to the baggage claim area. In the gate areas, there are lots of places to shop or get something to eat. The bathrooms were clean, as were the gate areas that I saw.
Two things I'm not a huge fan of - big bottlenecks getting off the train (ONE escalator going down to baggage, really?) and the pickup/rental/parking complex is pretty confusing if you aren't used to it.