Actually, federal income tax rates are higher in the US (10-35%) than in Canada (15%-29%) for most Americans. Of course State and Provincial taxes are on top and vary by location. Same for Property taxes. Sales taxes are generally lower in the US as there is no federal sales tax but they often have "local city" taxes.

If you lump all taxes and take into account medical insurance Canadians fair quite well. A more cost efficient medicare plan and lower military spending (1% vs 3% of GDP) has an impact.

It is not a simple comparison but in general poor Canadians do better than Americans and rich Americans do better than rich Canadians. So our doctor friend may be better off in the US but not by much.

Here's a good article - a little dated but the analysis still holds.
http://www.investopedia.com/financial-edge/0411/do-canadians-really-pay-more-taxes-than-americans.aspx