I'm a kiwi (Hastings, Wellington, Invercargill, Thames, Auckland), have lived in Oz (Newcastle, Boyne Island, Brisbane) and now live in Canada (Montreal).
While I would like to return to NZ as it is a fantastic place to bring up kids, I find it too small, a bit narrow minded, and too quiet. Last time we visited, we went to my Dad's bach with my stepsister and her 3 little kids were running around on the beach, just like we used to do when we were kids, and I feel heartbroken my son won't get to share that with his cousins. This is what I miss about home. If there was a big construction project on, we'd definitely go.
I enjoyed Australia, but found it hard to cope with the humidity and heat, and had an even harder time dealing with the creepy crawlies, snakes were fine, but the crawly things I couldn't cope with. It is a great place to live though. People are laid back and family orientated, based on what I saw in Brisvegas, and they would quite happily strike up a conversation while waiting to cross the road. And it didn't feel weird. We had the opportunity to go to Perth before we came to Canada, but just couldn't bring myself to go as it just seemed too far from anywhere.
I suppose that is what puts me off going home or back to Oz, they are both far, far away from Europe/UK and was the main factor in our decision for Canada.
This is my second time now in Canada, I have been through a winter, and loved every minute of it. We really enjoy it here. The city is just big enough without feeling hemmed in. We live in a lovely suburb, 10mins from downtown, with great leafy trees and many parks within 15min walk. Last time I was here, I remember walking home from work with massive snowflakes, as big as my fist, falling, just looking up into the sky in wonder. Locals must have thought I was nuts, but I do love the colder climate.
Canadians, extremely friendly and almost ridiculously polite, and everything is SUPER. We love it, and even DH, who has an extremely good reason to return to the UK thinks we'll stay for good.
Whichever you choose, it's a matter of getting into it as soon as you arrive. Invite people over, set up playdates, take people up on their offers straight away, immerse yourself in local friends. I've found that has much helped us here, where as when I moved to UK I was more reticent with this, and even though we lived in DH's hometown and did have friends there, didn't really feel part of the scene.