I will be honest. I have not visited Toronto and have only briefly visited Calgary, but Calgary is a much more car-dependent city, and it is much more suburban by nature. Toronto is much more dynamic in terms of transportation systems, however, Toronto is equally sprawling, but with a much more energetic downtown.
I wouldn't be too concerned with part time jobs though - I imagine you can easily obtain one in either city, depending on what you had in mind. Restaurant work, retail work, office work is pretty easy. Toronto would have more numerically simply because the city is about 5 times larger than Calgary.
Unfortunately not many Canadians use this board so you might not get a lot of responses from people who have a lot of experience working/living in both Toronto and Calgary. I hope a few others will chime in though.
