I personally have never had an issue with aus post, and I am addicted to online shopping. I've lived at various addresses and not one lost item or things being dumped. Once or twice they didn't knock at door but over several years I think that's pretty good.
Sure, their package delivery is expensive, but at least there are other options. I honestly have no issues with $1 a stamp.
It's hard comparing costs with Europe due to the sheer size of Australia and the rural communities spread throughout thus the increased expenditure in transportation.