I’m intimately familiar with both institutions.
How old will you be when you do this? You must be at least 21 to drink alcohol legally in Massachusetts; in Ontario it’s age 19. At both you could drink at private parties before those ages, but to go in bars (which is where a significant part of the social life in each city takes place), you would need identification showing you are of age.
What subjects are you going to study?
Do you like to watch sports? BC has the full array of top-notch university-level sports, and thousands of people attend its football, basketball, & ice hockey games. While UofT has teams in these sports, they are not popular spectator events.
At Toronto, students tend to be quieter in classes than at BC. If you want lively in-class debates, BC would be preferable.
Toronto’s campus is completely flat; BC’s campus is hilly.
Walk off campus in any direction at UofT and there are bars, restaurants, and shops right across the street. There arent many businesses adjacent to BC. Both have excellent trolley/subway transportation available.
Within a few hours of Boston there are a lot of things to see & do. There isn’t a lot to do within a few hours of Toronto, except see Niagara Falls.
Toronto is a bigger city, with fascinating ethnic neighborhoods, especially Italian, Greek, Portuguese, & Chinese. There is a huge Chinese presence in the city & at the university. Boston has some ethnic enclaves too, especially Italian, Irish, & Chinese.