In Sydney, most people know the Hilton for a number of reasons - Same location for years, (close to Town Hall,QVB, Tower) nice foyer, famous Marble bar, Zeta nightclub, Luke Mangan's restaurant - Glass, good reviews on TA etc.
Some things did surprise me however - given the reputation.
The rooms are the smallest of any Sydney hotel I've stayed in. (Almost Parisian in size, but we are not in Paris ) The Deluxe room was spotless and the bathroom looked as if it had been revamped recently, with a deep bath and a separate shower. However, I expected more than twin beds pushed together, with a doona barely covering the top of the bed and no top sheet.
It did have nice fluffy pillows, robes and slippers - all things expected in a 5 star international chain.
As no information on hotel facilities was given on check in, we went to explore. Following a rabbit warren of corridors via an under-ventilated gym and its change rooms we finally found the pool. It was under cover, had a low ceiling, chlorinated air and looked much better on the website.
A first for me in Sydney was - the electronically tagged items in the mini bar. If you remove something from its place it was recorded and you are charged a ridiculous price. If you want to store your own items there is a note telling you to ring and request another fridge for the room. (not sure where you would put it). Parents beware of little ones, or you will have a hefty bill on checkout!
The breakfast served in the popular Glass Restaurant was a nice buffet, with a range of hot / cold foods, made to order eggs, breads, pastries and juices. Pricey at $40 a head or $29 if you booked when checking in. However there are many cafes in the nearby QVB.

Location is ideal for tourists on a short stay, especially if you are able to get a good deal ($100- $150) Presently on sale for $250+ per night on their own site.
Being a Sunday, we managed to get a good last minute deal. ( I'm not sure I would pay the rack rate to stay here) Unfortunately, Zeta was closed and Glass was booked out for dinner. (There is a set course menu for in- house guests). Best to ring ahead and book if you want this offer.
Internet is complementary in the foyer but is slow and outrageously priced for room connections. Local phone calls are timed (unheard of in the rest of Sydney)
We did have a lovely view from the 33rd floor. The roof tops of the Town hall and QVB and the lights of Sydney by night - beautiful!
However, if you want a treat or something special book a corner room or suite which are bigger. Or stay else where (eg. QT, Shang-ri-la)

Pros: Very well located for shopping and well located for business. Modern fit-out. Standard of cleanliness is good. Quiet room with comfortable bed and electronic blinds made for a good night's sleep. Friendly staff.
Cons: Small rooms (a hang over from the original property), particularly the bathrooms. Can be slow at reception during busy times. Parking isn't cheap. Restaurants were closed on this trip, including for breakfast (on previous visits I was impressed with the main restaurant - very stylish fit-out and great breakfasts).

Firstly, we were fortunate to score an amazing deal (using Wotif.com's "mystery hotel" option) and spent 2 nights at the Hilton Sydney. Because we secured an AMAZING price, we were extremely pleased with our stay as we would not normally be able to afford the usual room rates.
The location:
It is extremely convenient - near Town Hall station (for the airport train), walking distance to Cockle Bay and Darling Harbour, and a stroll down to Circular Quay, The Rocks and other attractions on the Harbour. It is also in the main shopping precinct (Pitt St Mall and QV Building).
The room:
We had a corner room with views over the city, including the Centrepoint tower. The screens that can be used to keep the room totally dark were great for a fantastic sleep in! The room itself was reasonably large, lots of amenities (which we didn't use), very clean, and functional. The mirror on the wall was excessively large and unnecessary. The bathroom had a large shower (complete with TV screen) and lovely toiletries.
The hotel:
We enjoyed a discounted breakfast buffet at the Glass Brasserie which had a lovely spread of hot/cold and savoury/sweet items. The staff were very friendly. We even splurged on in-room dining whilst it was pouring with rain outside - the price for the chicken and salmon main dishes was quite reasonable and very tasty.
The facilities:
We didn't have enough time to check out the fitness centre
The minuses:
One of the fluorescent lights in the bathroom kept flickering for 2 days - we forgot to tell reception, and it was strange that housekeeping didn't seem to notice. The pillows were too soft (although we didn't find out until later that there was a pillow service!).
Overall we had a fantastic time, and it was made even more so because we had a bargain price!

We ate at the Hilton as a treat for the final night of our month long stay in Sydney. The restaurant was unbearably hot and when we asked the staff about the air con they admitted it was broken and had been all night. Although the staff could not have been nicer we were not even offered a complimentary drink and the heat really detracted from what otherwise would have been a very good meal. We feel that we should have been called and told about the aircon and given the option to cancel our booking, especially as it was mid January. Disappointing customer care.