I only know the details for Ontario and there's a lot of inter-provincial variation. Expect to get 6k-15k /year in government loans depending on your home province and financial situation.
The interest rate on Ontario loans is a lot higher than private loans (approximately central bank prime + 3.5%). The only advantage is that you don't need to make minimum payments on government loans while you're a student. Private lines of credit(LOC) have a minimum payment of about 2.5%/year even while you're in school. You can roll that into the LOC but that may impact your ability to fund the full 4 or 6 years if you're self funded. LOC also accrue interest during school while government loans don't.
Repayment on Ontario loans starts during residency (even though you're a fulltime student for all other aspects of the tax code) and can be quite onerous when compared to the LOC. The LOC can be kept at minimum payments until you're fully qualified. You can potentially reduce the government loan payments to interest only by making a financial hardship request every 6 months (which is useful but really annoying).
You also receive an income tax credit for a portion of the interest accrued on your government loans. But the higher rate on government loans more than cancels that benefit out. Ontario loans are tracking loans like the LOC and do not provide a buffer against a rise in interest rates.
One of the rarely discussed aspects of tuition funding is how Canada encourages education through the tax code. The US subsidizes student loans. Canada doesn't provide the same type of comprehensive loan but instead provides tuition and educational expenses tax credits which can be applied to future income. There is no limit to the amount of tuition credit you can bank to apply against your future income tax. That does shift a lot of the funding burden to the student years and makes the banks a lot of money BUT it makes repayment down the road a lot easier. If your parents or spouse is funding your education you can transfer these credits to them to offset the costs on an annual basis while you're still in school.
Tax credits are one of the ways physicians are able to pay off their student loans within five years of entering full practice.
For those of you in Ireland make sure that you're filing returns every year and collecting TL11A (
http://www.cra-arc.gc.ca/E/pbg/tf/tl11a/README.html) forms from your school so you can start banking credits.