I was with Aussie Broadband during my 2 years there and the service was fine. They gave sufficient notice for maintenance work and there weren't too many surprise outages.
Mobile reception might be a problem. The type of building you live in might make a difference; for example, I was on the 9th floor of a 17-storey building. One of my flatmates was on Optus and the reception was terrible, and personally I would have problems taking calls if I wasn't on the balcony.
Hope that helps!