We stayed at the Holiday Inn Darling Harbour for one night, the last night of our honeymoon in Australia. We got to the hotel at about 11:30PM after an evening flight from Cairns and checked out about 5AM to catch our flight home, so we were not at the hotel very long at all.
The hotel seemed fine - our room was clean and comfortable. We had a room on the first floor, which had a strange layout - bathroom and closet just inside the door, then about 4 steps town to a sunken bedroom area just big enough for the queen size bed. But furnishings were decent and everything worked OK.
The area around the hotel is really Chinatown more than Darling Harbour. There are mostly chinese restaurants in the area adjacent to the hotel, but we found a diner-style place that was still open at midnight to get some food before bed.
The hotel suggested we take the airport shuttle instead of a taxi - the shuttle picks up from the hotel every half-hour starting at 5AM. This was a fairly quick way to the airport and it was cheaper than a taxi, only about $10 AUD per person.

Whilst this hotel is in a good location - within walking distance to Darling Harbour the Front Desk service that I experienced when checking in was extremely poor. A queen bed room was booked but could not be offered to me as they did not have any of these rooms left. When I asked could housekeeping please come up and make the twin beds into a double for us, she rudely said that this could not be done due to the hotel rules, but if I wanted to make it up myself I could - this meant moving side tables, beds and requesting new sheets / doonas etc. - Not a great way to have to start your stay!
When we then enquired about car-parking the same lady on reception was once again very rude to us and could not even tell us where we should park - we had to go and locate the concierge ourselves to find this out.
The hotel itself is of standard quality, but beginning to show the signs of a needed upgrade.

After reading other reviews before staying at The HI, I was a little concerned. However, I was pleasantly surprised. The people at The HI were extremely pleasant and helpful. The rooms were clean and neat. We faced Chinatown. The view in our room wasn't the best. It was a brick wall and the roof of another building. I didn't mind though because we really didn't spend a whole lot of time in the room and when we did, it was only to sleep. The breakfast buffet was very good but was basically the same all the time. Know that you can ask for your eggs cooked to your liking. Transportation of all kinds were close. However, I wish I had done some research before hand on how to use it. The tram was easy to use but only went in a circle and made stops up to Cockle Bay and back. If you're going to take the bus, know how they run. Make sure you know the bus #'s and where they go and how to get back. The conceirge was very helpful for that. If you like to walk, there's a lot in walking distance. Especially Paddy's Market. Good shopping!!! Expect to spend hours there. Overall I had a great experience.

The hotel is located on the back of Chinatown in Sydney across from the convention center. Even though the monorail runs right outside the hotel, we barely heard any noise. The room was not that big but it was fine for us. The beds were all right too. The location is about a 30 minutes walk to Circular Quay but there are buses and trains near by. Even though it is near Darling Harbour, the walk to the ferry is not convenient. However, if you want to stay near shops, food, and street activity, then this would be a good location.