Pros: Most livable city in the world. Great startup scene. Phenomenal transportation options. Great universities. Fantastic street art everywhere. Amazing food. USD vs. AUD is quite good for USD right now so it is pretty affordable.
Cons: Internet not blazing fast. Beaches elsewhere in Australia are much better (it is on a bay = no waves).
I found it to be amazingly expensive (I was there in 2013) but a phenomenal place to explore. Made amazing friends and loved the city but don't miss the $44 burritos.