We stayed for one week in Silvias Appartement and it was really great. Silvia is so lovely and helpful e.g. she gave us information where to stay to see the firework or where to buy food.
Her flat is great: very clean, nice room, big bathroom and a barbeque on the bolcony which we used sometimes.
Kings Cross is a great place to stay in Sydney with Pubs, Bars, Restaurants... and only 2 trainstations away from Downtown.
The next time I come back I would stay again in Silvias flat!!