If you have never seen a rain forest, then the Kuranda trip would be nice. However, if your main thrust would be diving, then spend your time at your favorite sport. There are rainforests all over the world and very few great reefs and this is a trip of a lifetime--to see the Great Barrier Reef. And to dive as well! Time well spent, IMHO.
We did not find Kuaranda a great destination in comparison with the rest of what we visited in Australia and New Zealand and Fiji.
Gretchen, South Carolina