I've always been unsure about zoos. I don't like it when animals are seen as objects for entertainment. If there is a real attempt to understand the needs of wildlife in relation to their environment, then I don't mind so much. But when there are also programs to protect the environment, raise community awareness and rescue individual animals, then it is definitely worth supporting.
In the wild you can't count on spotting a Barking Owl, Platypus, Dingo, Koala, Greater Bilby, Red Kangaroo, Emu or Tasmanian Devil. In Healesville Sanctuary you will definitely see these creatures, and in as natural an environment as possible.
My friend S. from Scotland and I saw two orphan babies: a wallaby and a wombat. They were being raised by caring staff members, who took it in turns to take them home for night care and feeding. These animals need special lactose free milk, and staff take it in turns to take them home and feed them during the night.