com/sci combined degree gives you way more opportunities to study different subject areas through different faculties (arts, education etc), and you come out with a combined degree rather than just a singular degree, which can help with job prospects.
its an extra two years (you're essentially doing two degrees) and the combined commerce degree will allow you to focus on financial units that may not be strictly related to science and statistics, it will be more on the business side of things. but, either way, you could end up the CEO of google france, just sayin'. http://sydney.edu.au/courses/programs/science/Bachelor-of-Science http://sydney.edu.au/courses/progra.../Bachelor-of-Commerce-and-Bachelor-of-Science
