I was in Pittsburgh for a meeting and didn't have much time to see anything. This was the only place I saw and was really glad that it was the one thing I really experienced. The tour of the nationality rooms is only 3 bucks. You get a cassette machine with the audio tour recording and each person starts in a different room so that it's unlikely that you'll be in the same room as another tourist. However, this doesn't always work out. If you have headphones, it's a good idea to bring them so that you can listen to the audio recording while someone else is lingering in the room.
This is a highly recommended place to see. It's cheap and a great way to spend an afternoon. Like another reviewer said, take the elevator to the 36th floor and check out the view. However, you need to find the elevator because some of them only go to the 3rd floor.