I live in New Zealand, similar health system to Canada. I broke my pinky finger a few months ago, late-ish on a Saturday night - busy time for the drunks and so forth attending the emergency department. 45 minutes in and out, x-ray'd, splinted and with follow up appointment booked. A few weeks later I started seeing a hand therapist to make sure all the mobility came back, total of 6 visits.
No private health insurance, total cost to myself: $0
I travel to the states regularly for work (medical devices, so I see it from the inside as well) and carry a travel insurance card with at *all* times. I will not leave the hotel without it. The last thing I want is to fall down some stairs and break a leg, and then go through your healthcare system without insurance. The second to last thing is to go through your healthcare system at all - remember I see it from the inside as well. Not a great reputation for a country to have with it's visitors, really.