As far as zoos go this one is very good. Having worked at a zoo in the past I can say that the board of directors at Phoenix Zoo must be very progressive. The zoo is very focused on it's main target audience: kids. The displays are well done to allow small ones excellent views of the animals. A couple good examples are the Komodo Dragon exhibit and the new Orangutan exhibit. The open monkey exhibit is wonderful too. So much effort has gone into developing interactive and exciting ways to see the animals here. They put a lot of effort into showing animals together, the big savanna exhibit is well done with many animals allowed to free roam the large area.
It is a big departure from some of the more urban zoos and they have tried very hard to move away from the traditional concrete boxes that are more often seen in many of the older zoos. One disadvantage of this is that the animals have places to hide and sometimes are not in view. While this might suck a little for the humans, it is something that lends the animals a respite from the stresses of being in captivity even if just a little. One workaround is to come early, this also keeps one from dissolving into a puddle of heated goo as the temperatures climb (if you're coming in summer). We fixed this problem by getting a membership and coming during the member hour in the morning when we can. The animals are more active and so are we. I have had many wonderful conversations with keepers and docents alike here, we plan on keeping a membership for quite some time to support this wonderful zoo.