Canadian federal tax is 33% over 200k USA is 33% over 189K
Ontario taxes 11.16% up to 500k California 9.3% up to 250k
... Ok so realistically 2% in taxes :). Maybe that's not a total wash.
But if we're looking at the break-even point it might hit $3k in California's favor
check it out: https://github.com/bsurmanski/TorontoSFTax
It looks like between 60k-200k, taxes in Toronto are actually lower. Between 200k-700k, it is cheaper in SF. At 300k, Toronto tax is about 1.5% more, and at 400k, Toronto tax is about 2% more.
But being realistic, most people in tech would pay less tax in Toronto.
edit: This calculation also does not take into account any other taxes (such as sales tax, or property tax), and is not adjusted for cost of living. SF has an edge in sales tax (8.75% in SF vs 13% in Toronto), but Toronto has a huge edge in cost of living (according to [0], Toronto is 32% cheaper), and property tax (1.14% in SF vs 0.7% in Toronto).
[0] - https://www.expatistan.com/cost-of-living/comparison/san-fra...
[0] - http://www.investopedia.com/financial-edge/0411/do-canadians...
If you're making $500k, it also isn't likely a high point of concern.