Hello, I am not sure if this forum is only for computer issues but if so sorry to post this here. Right now I'm trying to decide which offer is the best way to follow a career either as a software/game developer or pen tester. So far I narrowed my options to University of Western Ontario, Computer science and University of Waterloo, Mathematics. Even though Western is offering cs which is what I wanted, I heard that Waterloo is a better university for both math and computer science programs. To sum up, which offer do you think would be more beneficial for my future career desires?

Waterloo is generally regarded as the better university for Math/Science/Engineering.
But Western is also quite good, and London is a beautiful town.
You won't go wrong with either choice.

You are essentially asking others to pick your preference.
Keeping in mind that you could go to the best University in the world, but if you aren't interested in your course of studies, you will do poorly or drop out.
Pick the one that offers what interests YOU