While we were in Arizona last week my mom took my sister-in-law and me (+ kids) to the Phoenix Zoo. I haven't been to the Phoenix Zoo in years and it has improved greatly since the last time I was there. I'm pretty spoiled though because I have an annual pass to the San Diego Zoo and frequently use it and, let's get real, the San Diego Zoo is pretty phenomenal.
The one thing that I think the Phoenix Zoo has done better than the San Diego Zoo is the children's petting zoo area. It has a great, shaded playground, real-life tractors and a really cute barn and yard for the animals along with videos for the adults on livestock and a cute foot-pumped water faucet handwashing station. William loves petting zoos so he had a great time getting to know the goats.