Lived in Sg for 6 years, Lived in Perth 3 years, Currently, living in Sydney for over 1 year.
In my experience..
Housing - rent-wise, Sg almost same with Perth, More expensive in Sydney.
Safety - Sg much safer all around. "Great enabler" ang Aus Government. Ang baba ng fines/prison time sa mga crimes, vandalism on buses and trains, may syringe boxes for addicts sa mga toilets, and there are really bad neighborhoods (uso break-ins, assault etc.) in certain pockets of both Perth and Sydney.
Food -Sg lamang dito, across the board. for 4-5 sgd sulit hawker food vs 11-14 aud for generic westernized asian food sa food courts sa mall. both countries varied choices naman.
Transpo - lamang sg being a small city-state (better, efficient bus and trains) dito mahuli ka sa bus eh minsan 30 mins na susunod.. Except sa pagbili ng kotse. you can buy a sh*t car here for 2 days worth ng salary mo. Eh sa Sg, COE pa lang yari ka na.
Stress - hands down, panalo Sg dito. work, school. KNN CCB.