I stayed at the Hilton Sydney for 5 days while attending a conference. The room was booked through conference organisers for a "reduced rate" of $299/night (room only). I discovered afterwards that I could have got a cheaper room through wotif.
Whilst the webpage states that the hotel is newly renovated, only some of the room have been renovated and I received a unrenovated room. Overall, the room was tiny and not what is expected from a delux "newly renovated' hotel.
The bath-tub was stained. The toilet flush worked intermittently and then continued to run water after flushing. The wardrobe door fell off its runners. The block-out blinds were sticking and wouldn't shut properly.
Whilst the location was good (opposite QVB), there are plenty of other hotels in central Sydney that would offer better value for money and higher quality rooms.

My wife and I stayed at the Hilton Sydney on the Easter long weekend 2008 and it was one of the most extravagant hotel experiences we have ever had.

The service was unique, with the staff managing to pull off cool, hip and highly professional at the same time.

On the Saturday night we had the hotel's famous 'Provocateur' package, which is no more innocent than it sounds. The package, that included lots of little surprises, also includes a selection of sensual foods in your Relaxation Suite and a bottle of champagne.

We spent one night in a standard room, and two in the Relaxation Suite. The standard room was finished to the highest standard and every attention has been paid to the details, from the furniture to feature walls. It was on the smaller side, but still had room for a work desk and large bathroom.

The Relaxation Suite was an absolute treat and is absolutely worth the price-tag. It provides lots of floor space and corner views of the city skyline.

The bathroom in the Relaxation Suite was fit for Hollywood, including an amazing shower with 5 jets (a rain jet from directly above, three body jets that sit vertically on the wall, and a hand held shower head). The bath was the biggest two person spa I have ever seen, and you could easily fit more people in there if that's your thing.

If you stay in a Relaxation Suite or on the Executive Level, you get access to the 36th Floor Executive Lounge. An intimate breakfast, refreshments throughout the day and cocktails in the evening make the lounge a perfect addition to a stay.

Overall, the service was truly 5 star, the internal architecture is breathtaking and the rooms are the best in Sydney.

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.