as a resident of neighboring highland park, i have experienced the zoo in many different ways...
there have been birthday parties, many years of zoo camp, learning to drive in the parking lot, working there for two summers in high-school etc.
while some aspects may be slightly out-dated, pittsburgh is lucky to have a zoo that has continually introduced new and updated animal environments. additionally, there are only six zoo's in the US with an adjoining aquarium, so that's also a huge plus.