IZM As far as I’m aware (please feel free to correct me if I’m wrong) for getting in, McRob is more competitive than Nossal (MacRob - 3+ superiors, Nossal 1+ superiors: give or take, you could still get in with less or not get with more all depending on the competitiveness of your current cohort) however, your preferences should be more focussed on what school you think would suit you better as a learner, as the schools are different. The most obvious difference between MacRob and Nossal is that MacRob is single sex (females), whilst Nossal is co-ed. Another factor you should consider is how far away these schools are from you - this is what pulled me towards Nossal over MacRob, as Nossal is only 10 minutes away from me, rather than MacRob which is more than an hour away. I can’t really go into specifics of the culture and learning style of each school, however, I’m sure there is information about this online - especially on the archived atar notes forum for selective school admission, which I found particularly useful when not only learning about other student’s experiences at selective schools and making my preference decisions, but also for practicing for the exam. If you have any other questions, I’m happy to answer to the best of my ability.
Best of luck for the test!