Taronga is a good zoo, but it certainly isn't the best in the world ( I don't even think its the best in Australia, that title should go to Melbourne Zoo). It does have the best veiws in Sydney being carved into a rocky hillside, but this location actually works against it at times.
The natural cliff faces work well attractive backdrops to the enclosure but severly restrict the design and depth to the exhibits. It really is just a very green and attractive Hagenbeck-style zoo with the animals randomly placed throught the park. It does have a resonable animal collection (but again Melbourne's is much bigger) and has alot of potential. I reccomend going back and visiting in about ten years when the Parks masterplan has been completed. In the meantime if you wasnt to stroll through interactive, submersive thematic exhibits like an African or Asian rainforest, touch an elephant going for a walk or actually learn about conservation visit Melbourne Zoo (sorry I know this sounds like a big Melbourne plug but it really is a much better zoo). Taronga, get your head out of the sand!