Climate? I think its much better in Sydney than in Melbourne and I agree with the costs and logistics. I think you will find a better peer startup community in Sydney compared to Melbourne. If I were to pick any other city other than Sydney or Melbourne, I think Perth is not a bad option.
Maybe it's just that Melbourne reminds me a lot more of the SF Bay Area while Sydney reminds me of LA.
Perth would be interesting if you could network amongst the rich mining types there. Could be a nice alternative source of funding. But I'm not sure how much software talent there would be there.
I must be missing something.
There is only 1 hackathon a year in Perth, compared to 2 or 3 per weekend in SV/SF.
I can count the number of co working space on my one hand.
It is a boring town unless you like the 3Bs: Beach, beer, and babes.
There is no culture here.
Sorry, opera theatres do not a cultural city made.
And the traffic jam is getting to be like Los Angeles.
Everything here (almost) is at least twice as expensive as SF.
The government is conservative.
OK, it is nice and safe to bring up a family and to retire.