I highly recommend this excursion to the Lone Pine Koala Sanctuary, along with the very pleasant Brisbane River Cruise. We enjoyed it thoroughly. It was a lovely day and you don't get too many opportunities to hold or pet a koala. I loved how open it was. You could just wander around areas with kangaroos hopping along or relaxing under a tree and the koalas were basically just hanging around in various tree settings with their eucalyptus. They were mostly just chilling or sleeping. Apparently, they do that about 20 hours a day. In order to hold them, you need to get into line right away when you arrive from the boat and be prepared to stand in line for a while. It's $25 AUD for one person to hold a koala, though another person can be standing there and still be in the picture. No regrets, but it did take some time waiting in line, which did impact the amount of time we had at other exhibits. That's one reason why I gave this four starts instead of five--I would have liked an extra 30-60 minutes because of how long it took to get through the koala line.
The other thing to know is aimed at cruise passengers. We were on the Majestic Princess, which was docked at the Fisherman's Wharf area. It was no where near where you need to be to pick up the tour. It took us a full hour to take the shuttle ($25 round trip per person) to Anzac Sqaure in central Brisbane, and then it was a good 20 minutes to walk to the boat. We made it, but not with much time to spare, and we left the ship as soon as we could get off in the morning. You need to be on the first one or two shuttles off the pier, around 8:15 a.m., in order to ensure that you have time to reach the departure point, and once you return in the afternoon, you need to get quickly back to the shuttle point to get back to the ship on time. Your other option is a taxi, but it is expensive (well over $100) and we experienced pretty significant traffic.
We loved the experience, but be sure you've added in enough time for the travel to and from the Miramar boat near the museum.