Omg, I feel like I'm in bizarro world reading this thread! Most of the negative comments about Oz are exactly the complaints I would make about England. I grew up in Sydney, live in Canberra now but did my masters in London. Now I know that London probably isn't representative of UK, just as my experience here isn't representative of everywhere in Australia but...
Racist: I have heard way more racist comments by english people than I ever have here. Now, I have lived in cities only here and work in a university but the english people I heard making racist comments were also students, so exactly the same sort of group.
Sexism: haven't really noticed much difference. Have had english men condescend to me, but the same with australian - I think this happens to me more than other people even because I am very short. I did find that english culture was way more sexualised and that girls were more openly promiscuous (have never been told by a casual australian acquaintance that she 'pulled' last night). I'm not sure what to make of that.
Rude: I was left reeling by the rudeness and aggression of Londoners. Couldn't believe the way people bumped and knocked me on the street. I spent two months on crutches and no one ever ever offered me a seat on the bus. I found it hilarious after I got over my shock and got very good at asking people to stand up for me (maybe they thought rude aussie???). I would never live in London again because it is just too stressful.
20 years behind/no culture: Don't get this at all. I used to follow the culture scene quite closely before ds and couldn't see a huge difference. I must say I did find that attitude and education at UCL, where I was studying, seemed very old fashioned and conservative to me. I don't actually think this is necessarily a problem (could probably do with a bit more of it here) but it did surprise me.
Climate: Yes, if it does actually get cold in Sydney then it can feel cold inside because not everyone has heating. I've noticed this myself since living in Canberra where it does actually get cold in winter so most people do have proper heating. But you can always get heating. And it is far less awful than a stinking hot summer in London where there is no where cool to go, the air con that is around stops working and all the fridges in the shops break...
Fruit and veg: ???? huh??? I did actually notice that you had a wider range in shops but that is because it is all imported and out of season!!! This seemed to be a big problem for a lot of people, from the number of articles in the Guardian about it at the time. Maybe our way is not so bad.
Gem, I think you mentioned you were interested in Canberra? Canberra has a bit of bad reputation for being boring in Oz. I really love it - easy to get around, fresh air, friendly people, great for kids. Small town benefits but more of a city culture/feeling (if that makes sense). No beach, which I miss a lot. It has a transient population, so maybe easier for making friends? I find that a bit sad though, because people you make friends with then move away.