The advantages are more subjective than objective. Some people seem to think that selective school students get "scaled up", but in truth, this is really situational and doesnt have that much of an impact. The subjective benefit of a selective school is that the competition and environment motivates people to do better. However, that isnt true of all students - for me, I never excel in that type of environment, I perform much better in a chill environment (not too mention I'm a million times happier). I choose my local HS over a mid-tier selective school, mainly to be with my friends and because I liked the school. I'm in my early 20s now and those people are still my friends - looking back, it was definitely the right choice for me because I was happy and that kept me motivated. Even if I could have got 2-3 ATAR points higher at a selective school, it wouldnt have been worth it for me (to be honest, I dont think I would have done better elsewhere anyway).