We stayed at Sarah & Reza's place for ten days on our family vacation during Christmas. All my communication was with their co-host Sean who was very helpful and friendly. They allowed us to check in early and were very friendly and helpful through out the communication. The place is perfectly placed close to the CBD. You can catch the light rail at China town (10 to 15 mins walk) or the train at central station (15 to 20 mins walk) to all the CBD attractions, 10 mins walk to Haymarket, 15 mins walk to Darling harbour and the fish market.
The place is nice and clean with lots of space for a family vacation. I would definitely stay here when visiting Sydney next time.