Congrats on the 720! That's a great score and you should be thrilled. You'd probably have more luck trying to specifically contact Melbourne Business School alumni. These are the three questions I think you need to answer before you come to a decision:
1. What is your dream job? Be honest with yourself. What field do you see yourself in, and what program is specifically tailored to get you there? This may mean a lesser known school will actually benefit you more long-term if it has a specialized program you can't get anywhere else. If general management is your thing, it won't matter as much, but the business world is increasingly diversifying, and you should take some time to consider your role in it.
2. Where do you want to work post-MBA? They say the most important words in real estate are "location, location, location" and it can be true for business schools as well. If you know you want to live in a specific geographical area, such as New York, or in Europe, it makes sense to take a good look at schools that are location in the region, and have strong ties to businesses there. You'll be hoping for some type of help with career placement post-MBA, and your school will have the strongest ties to the companies in its own backyard. Location can also have an impact on your happiness while you pursue the degree. Would you prefer to be in a big bustling city, or a smaller close-knit community? Every campus has its own "vibe" and you should make it a point to visit the schools that interest you the most. Make sure to take a campus tour and sit in on classes to get a feel for the teaching style.
3. What's the ROI? Your degree is an investment. You'll be putting thousands of dollars and hours into earning your degree, so make sure it's worth it. School tuition rates can vary quite a bit. Is it going to be worth it to you? Do your research on the alumni from each program. Find out where they are working 2, 5, and 10 years out from their degree. Is that a trajectory you want as well?