The rivalry between the cities was the reason that neither Melbourne (the largest city at the time) nor Sydney (the oldest and now largest city) was chosen as the capital of Australia in 1901.
Sydney, with a population of 5.23 million, is the largest city in Australia, and has been named the world's best city eight consecutive times byConde Nast Traveler. Melbourne has a population of 4.94 million, and has been named seven consecutive times as the worlds' most liveable city.
Sydney is renowned for its beauty, great weather outdoors lifestyle and gorgeous beaches. Melbourne is the sporting capital of Australia, and likes to call itself a cultural capital with a large number of galleries and museums. Although the weather can be cold in winter and hot in summer, Melbourne is also a mecca for foodies and is known for its great shopping and cafe culture.
Both cities are safe and friendly, and if you have to choose...I think Sydney is better but shhhh....don't tell anyone from Melbourne.