Lovely apartment and very central so nothing is very far away. We stayed 5 nights over Easter with two children (4 and 7) and was comfortably enough room, amazing value compared to what you would get in a hotel for the same money.
If I was to nit pick it would have been nice for at least one of the three TVs to be connected to a standard antenna, staying 5 nights there are programs ourselves and the kids would have liked to watch during our stay.
A really useful tip I wish we knew when we arrived was that if you are bringing a car (hire car in our case) the "255 Elizabeth St" named car park doesn't actually have an entry on Elizabeth St, was very confusing to find the first time as the car park entry is across the road from the apartment at 242 Castlereagh St.
We had a great stay, the communication was great from the first time we booked to when we left. We would recommend to friends and family and hope to return when next heading to Sydney.