The Potter Park Zoo, Binder Park Zoo, and John Ball Zoo don't get a lot of recognition. I'm guessing it's because the population isn't as dense as it is around the Detroit Zoo, meaning they aren't getting as many visitors as Detroit. They aren't as great as Detroit, but they do have some really nice exhibits.
Potter Park Zoo has a pretty good black rhino enclosure. The zoo is also pretty small and doesn't have a lot of exhibits, but they all seem to be well designed for all the animals.
The Binder Park Zoo has an amazing African section with a huge savanna exhibit. The whole area is probably about half of the zoo. There is also a pretty good wolf exhibit and snow leopard exhibit. Honestly my favorite zoo out of these three.
The John Ball Zoo has a really nice aquarium, chimpanzee exhibit, and tiger exhibit. The zoo definitely has more of a modern feel to it, unlike potter park which has kind of a historic feel, or Binder Park Zoo which feels more like walking through a forest.
Now, none of those are the greatest zoos ever, but I honestly think they deserve more recognition. There are also some rare animals here that I haven't seen very often.