I have always preferred the Westin in Sydney to the Sheraton - I'm not sure why, they are geographically close, and the Sheraton is a little bit older (but only by 9 or 10 years), but this time I ended up at the Sheraton because the Westin was $200 more expensive.
Booked and recieved a Club floor room - the club is one of the best features of the Sheraton on the Park, located on the top floor of the hotel with large windows overlooking the harbour and park - a very nice place to grab a drink at night (complimentary) and breakfast in the morning.
Room was acceptable - bathroom was nice, with a good range of toiletries provided.
Staff in the lounge are excellent.