The most important thing is how you fit with the environment. I went to a big expensive undergraduate, and it was worth it, because it was an environment in which I thrived, but I know people that went to the same school and just burned out. It's like joining the Marines. Some people love the military life, but some people hate it.
One problem with these sorts of discussions is that it's impossible to redo history. I *strongly suspect* that the reputation of my undergraduate university really didn't help me that much, but it's impossible for me to know. Part of the reason it's hard/impossible to rerun history is that if I had gone to another school, I would be someone else. One reason that it's important to talk to alumni and upperclassmen is that often the choice of school ends up doing a decision on who you want to be, and if you talk to alumni, you'll get a hint of what you'll look like in ten years.
I got accepted to University of Toronto for physics
So I would like to know more about my future undergrad
It would be amazing if upperyear students from university of toronto (preferably st.geroge campus) tell me about the school
1. School life
2. Research opportunity
3. Competitions and grades
4. ummmm would you attend it again if you had a choice?
5. overall satisfaction....