I spent four years in Pittsburgh at Carnegie Mellon and another year telecommuting for work. The city has a lot of things going for it: a great collection of museums, some gorgeous parks, and lots of good food.
A couple places you should definitely visit if you find yourself in Pittsburgh: The Point, Carnegie Museum of Natural History, The Mattress Factory, Andy Warhol Museum, and the Southside.
Unfortunately Pittsburgh is in a lot of ways a dying city. It is the only big city in the US with a metro region that is declining in population. There has been a big push in recent years to try to reverse this, but only time will tell if these efforts will be successful.