As a local it is always interesting to read reviews of this hotel from interstate or overseas guests. I also prefer this hotel to the Westin, due to location, and that they generally offer a more personalised service, particularly if you stay more often.
Was a little surprised at one of TravelinSperry's comments in regard to room size.
Most Sheraton rooms are 35 square metres, with deluxe rooms at 38/40 square metres. Westin rooms are generally 38/44 square metres. I know there is not much in it but in general I have found Westin rooms larger.
The lack of lights overnight is surprising. Would have thought if brought to the attention of front desk a room swap would have been offered, unless hotel was full due to the tennis.

The hotel has 174 rooms, with only 11 suites. Suites are not particularly large.
Your chances of a Suite upgrade are not great.

It's not surprising that the hotel has no Club Lounge. It is boutique in style, and really doesn't have that many rooms. Westin doesn't have a Club lounge either though both Melbourne Hyatts have Club Lounges.
I would have thought that the distance from the Sheraton to Chinatown was very similar to Westin and Grand Hyatt. Park Hyatt is further away.