1) You will likely pay more in taxes in California than Canada.
2) It's easier to itemize self-employment tax expenses in Canada, so you can easily pay half the taxes of the US. (I paid 12% of total income the last year I worked in Toronto.)
3) Everybody I know in Canada is happy with health care, and infinitely happier than Americans who've received false bills.
4) Startups have a big advantage in Canada because of the state health care, and unrelated lower salary expectations.
However, salaries are lower in Canada because companies pay less (like Europe or anywhere outside the US), but that's not related to taxes or health care.