Did the Island Suntanner (same tour as bush to beach minus the red cetre part) back when Topdeck was still Connections, which is a really award winning company in Australia, and I would assume they still operate to the same standards. I loved their tour, I was also looking at Contiki as well, however, I thought Connections (Topdeck now) offered a much more all encompassing overall great experience, as I got the impression Contiki was more about how much partying they could do. Accomodations were nice, sometimes the quad share rooms got a little tight, but nothing too extreme. The tour included a lot of delicious meals which saved money, and there were plenty of optional activities. There is quite a lot of ground covered so a good comfortable time on the bus is essential too.
Hope this helps.