it depends on a lot of things like: are you super proactive and involved in lots of extra curricular activities? did you get a high 90's atar and think youll be able to get a super high wam consistently? What are your goals and aims in terms of money and living arrangements for university?
I do think the commerce degree at melbourne would be a bit better for most people. at the top end, it matters less if you have a really high average and are involved in lots of events and are super pro-active, in which case it would be pretty close between the two uni's and you can flip a coin, but if you think you will be between the 10th and 95th percentile of your commerce cohort I think Melbourne would be better. the on campus recruiting and networking things that are offered make it so that someone with an average in the 60s & 70s can still very easily get a really good job at companies that throw resumes in the bin if they see a non go8 uni on there. I really dont know anyone from my commerce cohort who graduated this sem who hasn't got a job lined up for next year but most of my monash friends didn't find anything and have decided to enrol in a masters or add a double onto their degree because their search wasn't getting anywhere, and they mostly had high distinction averages and good extra curriculars/case competitions etc. Of course my personal experience is anecdotal and from a small sample but at melbourne alot of opportunities just come knocking all the time. A lot of the larger networking events happen across both uni's and are run by certain clubs but at melbourne you have situations like lecturers emailing the whole cohort for a subject saying "my friend X needs analysts in this new team at this company so here is a google doc for you guys to apply for it" and all the people who ended up with the job would be people from melbourne uni's 1st sem investments cohort who got that email from the lecturer LOL. For that reason I would probably still pick melbourne over monash even with the 8K scholarship. I got offered a good scholarship to go interstate for my uni and I knocked it back for melbourne commerce based on the advice other people gave me which I am passing on now and I don't regret it at all. I definitely think living at home and being broke and having to work alot over the holidays for money is made up for in the fact that I have had some pretty good job opportunities for next year and eventually selected one that I am super keen for, at a smaller company where all of the employees went to melbourne uni except for a friend of the boss who went to RMIT. Also I'm not too sure on monash's policy regarding exchange and stuff but I know melbourne uni has been super chill and awesome. You can independently organise study abroads that you can take over any holidays (summer/winter) or during any semester (as long as you have no melb uni subjects that sem) and go wherever will take you. A lot of commerce kids in second year spend the winter break doing a few commerce subjects at the london school of economics or harvard summer school and stuff like that. You can most likely figure out how to get something like this going at monash but I am not sure.
Anyway just go with your heart, goodluck !