To a great extent your decision should hinge on where you want to work. Schulich is an outstanding school and is well-known throughout North America. I am unfamiliar with Melbourne, but suspect that it would be an excellent degree if you want to work in Australia. One approach is to look at where the graduates of each school end up working. Most schools will post at least a summary of placement results. If you know where you want to work and what you want to do, look for a school that is already placing people in that area or that field. Networks are generally strongest in the area in which the school is situated. Again, schools can be a great source of information. Find out where they have active alumni groups. Salary figures are also often reported, but the differences in cost of living make those less reliable.
Congratulations on acceptance to two fine schools.
Tani Wolff