I interviewed at UPMC but ended up at one of the other Pittsburgh programs. From what I heard and saw regarding their residency, it truly is one of the most resident friendly programs in the country. In fact, I have several friends from there who had a step DOWN in quality of life after starting a real job!
Regarding the city if Pittsburgh, I can say that it was pretty awful. The weather is really lousy (most cloudy days in the country), traffic sucks due to all of rivers/tunnels/bridges, people are NOT friendly, dirty city, the steelers suck, etc. And housing is cheap because nothing has been built since 1960 or earlier. Expect to pay at LEAST 3% property taxes and you get to pay 3% of your income to the corrupt city government. Did I mention that the Steelers suck?
That said, UPMC seems like a good enough program to put up with all that is ****sburg.