I'll be very honest. I think that every medical school in Canada has specific advantages and disadvantages. These include tuition costs, structured curriculums, and home province exclusivity.
For example, Ontario has recently de-regulated the medical tuition fees. I believe that tuition for each Ontario medical school is now near, if not above $10,000 per year. Contrast that with the paltry $4000 I pay at UBC, and that extra $6000 dollars a year gets pretty significant after 4 years of school. Because of the money I saved, I can afford to blow more of my money on getting higher quality medical equipment (cheap stethoscopes run near $100, quality ones up to and past $200), and more and better textbooks. You could also use that money to find better housing closer to your school, and a whole host of other things that will make med school easier and more enjoyable. Think weekend holiday trips! :)
Unfortunately, UBC is undergoing a flux in its curriculum. We are the third medical class since UBC totally turned the old curriculum on its ear, and adopted a PBL (Problem-Based Learning) teaching approach. When you realise that ALL of the teaching staff were educated in an era when PBL didn't exist, and they have taught for many years using a lecture-based approach, you have to appreciate that there are many growing pains as both teachers and students learn the new teaching/learning style of PBL.
As for home province exclusivity, if you don't have BC residence status, you probably won't get in here. UBC only accepts around 2 out-of-province students per year. If you don't speak French, entry into the Quebec medical schools is extremely difficult. As far as I know, the only two medical schools that didn't discriminate against out-of-province students this year were Queens and U of Calgary. Calgary is changing that for this next year; they are now imposing quotas like most other Canadian schools. To my knowledge, that only leaves Queens.
For that reason, I wouldn't worry so much about getting into a great medical school. Ultimately, you just want to get into ONE. That school will most likely be the one in your home province. Just like university and everything else in life, you get out of med school what you put into it. And never forget, even if you graduate last in your class at the worst medical school in Canada, you're still a Doctor. This doesn't make you stupid, far from it, especially after you consider the amazing qualities of each of your classmates.
As for the top five medical schools, I suspect that the top ones, in no particular order, are: McGill, U of Toronto,
U of British Columbia, Queens, and U of Alberta. Good luck!