5 stars for the main concert hall. I rushed to buy tickets before I flew in and was only able to get a seat near the very back but the acoustics was great! It was a sold-out classical performance and they were recording a CD. Sitting in the very back, the attire was very casual as it was almost all tourists (for those who do not like talking though, note that some ppl talked almost throughout); some even had small packs.
2 stars for the tour. I paid for a tour for the next morning (you do not have to pre-book even though I did) and many of the videos shown skipped / didn't work and the tour was heavy relied on the videos. That said, we saw many different halls which you otherwise would not have a chance to see unless you bought tickets for performances in each one.
If you own or manage Sydney Opera House, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.