Who would have thought that this question would get so many answers !!
I have been to oz twice, but only as a tourist, but I much preferred Perth to Melbourne.
Perth was sunny, accessible,friendly. Melbourne was massive, wet, and a pain to get around.
On this site though it does seem to get bashed up and many peoples answers and conclusions revolve around the recent boom and money and not the geography or people.
Like Ali says, a lot of people that bash it on this site prob have not been there.