While I may not be an expert on this, I will give my biased opinion that you are better of doing your residency in the US. Though I do not have any first-hand experience, I have read extensively other comments online from IMGs in Canada.
I guess it’s just difficult being an IMG in Canada. I believe they are trying to make things a little easier now but I will still recommend sticking with the US. Can you practice in Canada with US training? Yes, you can, with some caveats.
Depending on where you end up working (academic institution or private organization), you may need to write the Medical Council of Canada Qualifying Exams(MCCQE) part 1 an 2; you can be exempted from the Medical Council of Canada Evaluating Examinations (MCCEE) if you are already Board Certified in the US.
You can check the Medical Council of Canada website (www.mcc.ca) and the Royal College of Physicians and Surgeons website ( www.rcpsc.medical.org). It is always wise to arm yourself with enough info before you make your decisions.
Like I said initially, this is simply my biased opinion.