I stayed here for one night in October last year. My friend made the booking and asked for a non-smoking room.
When we entered our room, the first thing that hit us was the stench of smoke. We both became annoyed. Once my friend made a call, our request to change to a non-smoking room was granted.
A person was sent to help with our bags, however he did not take any of our bags. Admittedly we had guests with us at that time - four girlfriends - however he should at least have taken the bags of my friend and I - those paying. I had packed an overnight bag and had been given gifts that day, so I had additional things as well (My lovely friends helped me move).
My room key also did not work so I had to return to reception and get another.
The room itself was small in comparison some of the other comparable hotels I've stayed at in Sydney. It had the usual things you'd expect from a five star hotel. I liked that the mini toiletries were La Source by Crabtree & Evelyn - my favourite out of the hotels I've stayed at.
Aside from the room error and non-existent service from person that came up, we enjoyed our stay.
The gym was the best one I've used in a hotel. It had a variety of machines, a mat work area (for stretching etc.), group exercise studios and a pool suitable for laps, as well as large steam rooms. Unfortunately the jacuzzi was out of order when I stayed there.
Buffet breakfast was included in our package (which was about $300) and there was a lot of variety on offer. I quite enjoyed one of their custard donuts.
My friend and I were also happy that check-out was 12.
Would I stay at this hotel again? I'd recommend other hotels to those who want a five star stay, such as The Observatory Hotel.

Knowing we were using Hilton honors points for a free stay we were expecting the smallest room looking over the dustbins at the back.. What we actually were given was a superb suite on the 31st floor.

Large bedroom with a super comfortable super king size bed. Hi tech hi spec bathroom, all glass, mirrors and marble. Two person Jacuzzi bath right under a picture window. Great view of the Sydney skyline as you sip your evening champagne and watch the flat screen TV in the bathroom wall. Walk in shower with 5 separate heads. Two hand basins and separate toilet.

Next to the bedroom, an equally large and equally impressive lounge and hall area with another toilet and in all 3 flat screen TVs scattered around the suite. A telephone and communications system that you probably need a pilots licence to operate.

And all this done in exquisite simple modern taste.

The Hilton is downtown whilst most of their competitors cluster around the harbour. But downtown is great for shopping and restaurants and it is only a 10 minute walk from the ferries.

Undoubtedly the Hilton Sydney is, for me, the queen of the Hilton group in Australasia.

Stayed at the hotel for 2 nights and really enjoyed it. The other reviews are correct about the size of the rooms, but they are quite functional. I used points to stay there, but would not have paid the asking price of $375/night. The location is great and staff was very professional and accomodating. One nice feature are the automated blackout blinds. I woke up one morning around 9AM thinking it was 2 am. When I raised the blinds it was a very sunny day. The beds are very nice too! If you were paying, you can probably find a hotel with a bigger room, but not as nice. If you are using points, I would highly recommend using them at this hotel.

Stayed here twice during a recent visit to Australia
Re-vamped rooms and excellent central location. Business / Executive floors get additional service and the Executive Lounge for the complimentary breaksfast and pre dinner canapes and drinks is excellent.