From night 3 to 5 we stayed in the Four Seasons Hotel in Circular Quay. This hotel had the primary photo that I wanted of Sydney and I opted for the premium King Deluxe room with the Harbour view, on the 32nd floor.
Unfortunately, The sky was never really 100% during our stay and we had to contended with rain and ordinary cloudy days.
The area for shooting in the Four Seasons was also challenged with a small ledge and shooting through double glass windows. Fortunately I was prepared with a table top tripod and Platypod grip system.
Shooting through glass is challenging when you have less than clean windows that can not easily be cleaned, and light reflections from the room. Whilst shooting through glass the smallest light source from anything (mobile phone, light leak from under the door) can ruin your shots. Ideally you want to press up hard against the glass but that often restrict the composition.
Three hotels share the similar vantage point. These are Four Seasons, Shangri-la, and Quay West.) I would think Quay West would be the best choice, because it seems they have private balconies.