I'm currently at SIBT now. No, really. I'm in the computer lab at this very moment. It's my last week before exams, then I'll be at Macquarie in the first semester of this year.
I'd definetly recommend SIBT, class sizes are smaller than Mq and apparently the material is spread out over a slightly longer semester. Also, if you do a standard diploma (as opposed to advanced), you can do three units in your first two trimesters, and two units in your last trimester. Although you can definetly opt to do more if you wish.
I'll be finishing up here with a GPA of 3.0, a credit average. It's been pretty good here, I'd definetly recommend it if you can't get direct entry to Macquarie.
As for how likely you are to go on to second-year Macquarie, well that's all up to you. Do well and you're guaranteed entry to a second-year Macquarie course. You just need to complete 8 subjects, with at least 7 passes, and a GPA of 1.5 or better. Although higher-demand courses such as Applied Finance require a GPA of 2.25.
It's just like first year Macquarie, except there's a lot more international students here, it's like 80% international students, and 20% local students. Definetly consider it, just apply yourself and avoid failing any subjects and you'll be in a second-year Macquarie degree before you know it.
Time to go to my Stats tutorial, good luck with it. Message me if you got any questions.
Cheers,
Luke.