I don't do biomed, but I have a couple of friends who do the course, at Melbourne Uni and at Monash Uni! From what I've heard, they're both very competitive environments as most students intend to gain admission to med school or into dentistry or optometry etc. I feel like Melbourne Uni may have a slightly higher calibre of students, given that the ATAR requirement is much higher (something like 98+ I think?), and it really depends on the people you hang around with, whether they can be ultra competitive or supportive (I've met both types). However, in my personal opinion, I think that Monash Uni may be a better bet, as there are guaranteed spots for Monash biomed students for the med program, which is less risky than Melbourne Uni (there's a similar program where if you get some sort of ATAR like 99+, as long as you maintain 'x' GPA, you'll be guaranteed a spot in the med program and don't have to sit for the GAMSAT).
Melbourne Uni is yes a much more beautiful campus, and it is within the city and such but I would recommend to compare the subject units and take travel time into consideration!