In terms of reputation, UofT is just as world-renowned as Cambridge, if not more. It only happens that Cambridge is quite a bit older and people somehow associate that with "better". I've personally visited both schools and seen both facilities (but for medicine) and I can definitely say that personally, I like the way UofT operates much much more. Of course, there's a special respect held for those who can add Oxon. or Cantab. after their names, but UofT has been and continues to be one of Canada (and North America's) leading universities, sitting on top with McGill and UBC.
When it comes to employers perceiving degrees, it's rare that someone be hired just based on their alma mater. When you're looking for your first job or internship after graduation, usually you will have to supply your transcripts as well as a CV. Those and interviews will be what decide whether you get employed, not where you got your degree. That being said, you should also consider where exactly you wish to work afterwards. Canada is abundant in natural resources and Ottawa is rolling out a ton of new projects that require a lot of engineering work (such as the Keystone pipelines,the Inuvik road, etc.), so depending on the type of engineering you wish you study, that may also be something worth considering.
However, you should know that a Canadian citizen can work anywhere in Canada and relatively easily in the US. A British citizen, however, can work almost
anywhere in the EU. Note, though, that it is not easy becoming a British citizen and can take up to 5 years,
not including the time you spend there as a student with a Tier 4 visa, because their student visa is granted on the expectation that
you will leave after graduationwhere as an immigration visa is granted on the terms that
you will stay and work and contribute to British society. There are also EU laws which stipulate that certain employers must give jobs to EU citizens over non-EU people, if they offer the same qualifications. I am not sure if this will hinder your chances at finding employment there.
Lastly, you should also think about where would make you the happiest. You will be spending around four years in a place for a lot more than just studying. Cambridge is full of history and you'll be able to travel around the UK (and Europe) by hopping on a train. Toronto and the GTA is one of the most vibrant cities in the world and it is currently the economic centre of Canada. Toronto is a lot more than just a "university-city" and Canada is arguably much more advanced in terms of human rights.
Hope this helps!