they're very different. if you read around the threads you might get an idea. academically mhs ranks higher but in 2014 schs had a student get 99.95 and mhs didnt.
you can do equally well at either school, it just depends what sort of person you are. mhs has lots of mandatory extra-curricular activites, kids get involved, its more strict but people do well. its motivating and its sincerely about more than just marks
at SCHS you have all the same opportunities as you do at MHS but its much more chill and basically no one is forced to do anything.
in year 12 there would be people who would barely go to school and when they did they wouldnt be in class they would study in the public spaces, and in class you see people using their phones and on their laptop (being quiet) and in general its alot more chill and requires self motivation. people would even go in like semi-casual clothes like just the sport top, random trackie pants and a non schs hoodie (LOL)
if you are self motivated or quite different in terms of your study habits and hobbies etc then maybe schs is more flexible but MHS is a probably a better environment to be in overall. some people go to schs and get lazy and then end up with atars in the mid-low 80's. mhs motto is "more than just marks" which is pretty reflective of the school.
*i've got an example for how schs is flexible and how it could either allow you to be way better than a conventional class would allow or get distracted and do worse. my mate went there and every class he had, he and his mate would walk into class, stay for the first 5 minutes when the teacher updates everyone on deadlines and outlines what they'll be learning today, then the two of them would just leave the classroom and go to one of the private study rooms and just do work by themselves with no teacher supervision, separate from the rest of the class, for the rest of the period. this rooms are like separate from the main areas so you could go in there and be watching funny videos and laughing and doing no work or you could be in there smashing through exercise after exercise of methods work. its really up to you what you do with that flexibility.
if you get into the school you obviously aren't dumb so people don't really abuse the freedom, but there is the odd case of people who just never do work.
but the flexibility is great if you're the kind of bloke who likes to sit there in a solo environment or with a couple of friends and just brainstorm for subjects or smash through the work without the distractions of a normal class or having to go at the pace of the teacher. this is particularly good for high achievers and shit who dont want to have to sit in class for 20 minutes of teachers teaching when they already know what is being learnt. or on the flip side you might be quite far behind and the teacher will be teaching stuff that builds up on ideas that you don't know, meaning that its going in one ear and out the other. but if you can study by yourself you can use that time to catch up instead of trying to build a roof on a house that has no walls.
i feel like in general the MHS environment moulds you into a certain type of person. they tend to study hard, be outgoing, confident, reasonably sporty, etc.
SCHS doesn't mould you into anything, it gives you the clay and says mould yourself into whatever you want and we will accomodate
just my 2cents havings lots of mates from both schools over many different cohorts
EDIT: Added the paragraph with the red asterisks