First off, congratulations on such strong offers.
Both Rose and U of Toronto offer excellent Comp programs. However, Rose’s undergraduate program is far stronger than U of Toronto’s. Class size tend to be smaller at Rose, which can be a strength or weakness depending on your preference. If you thrive on diversity and people, head to Toronto.
On the employment part, I strongly disagree with tsbna44’s reply.
Graduating from such high-calibre colleges with a well rounded academic experience will get you good employment. Most employers don’t view nationality as a barrier, atleast in the States. Infact Rose has one of the highest and most amazing placements. U of Toronto doesn’t provide it’s placement rate, but its general salary statistics show that it’s Arts and Science department’s grads are one of the most sought after employees in Canada.
I can’t speak much of Toronto as a city, but Rose is isolated, even depressing. The RL does compensate for it, and there are events and parties happening on campus.
As for ‘Prestige’, rankings can be very misleading. If you focus on undergrad rigor, Rose is up there with the top CS programs while U of Toronto’s CS program is one of the best. Academically, you can’t go wrong with either.