I ranked this a 5 star attraction not because I absolutely loved every minute that I was there (I am a nerd at heart), but because my wife (who is as far from a nerd or museum lover as you can get) had such a great time. We visited Sydney for 6 days in June 2013. I had wanted to visit the Barracks for the history (housing for convicts), and because I knew it would give me a good summary of Sydney history, etc. I knew that my wife was going to be somewhat disinterested, but I pushed my luck and "just happened" to wander up on it when we were walking around. We went inside and spent nearly 2 hours touring what is a fairly small 3 story building. We got the complementary audio tour speakers, and we visited every room listening to the history and looking at the displays. There was a time I asked my wife if she was ready to leave and all she said was "Sshhhh" for me interrupting her audio commentary. I guess that was OK with me. She was entertained and I got to look around more. The Barracks does a great job of showing and telling the history of the founding of Sydney (convict history), specifically how the Rocks came about, and how the Barracks changes purposes over the years. Amazing that it barely survived being torn down. It does require climbing stairs to get to the 2nd and 3rd floor, so may not be fully accessible to those with mobility issues, but the grounds of the barracks are spotless. Well worth your time if you are looking for a history lesson. There is a small café for food, and a souvenir shop (which is really small). The barracks is on the corner next to Hyde Park, between the park and the Botanical Gardens, so relatively easy to find. Note: I uploaded a photo of my wife in a hammock living the barracks lifestyle.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.