I chose ours because it had a really good reputation. It's a public school but I love it. They have friendship groups for lunchtime and grow their own vegetables and use the vegetables in tuckshop
They do music and sport but I didn't care that much about extra activities because I would prefer to just take the kids somewhere myself so they end up with friends from different places. Not just school. So if they fight with school friends it doesn't matter as they have friends from dancing or swimming or wherever. At the moment they do 3 activities each and I prefer that to it all being done through the school.
I went to a private school and we did heaps of sport/music through the school, but it became our whole lives and I always noticed how much worse kids seemed to handle it who really only did things through school, and those who went to different sports clubs or whatever. Mind you, it was hard to go elsewhere because Saturday sports and that kind of thing was pretty much expected.