Estate taxes are retarded to begin with, this is just ridiculous. Why don't these people just give as a gift all their stuff to their kids while they are alive? Canada might have a 5% GST tax, but we don't have any of this nonsense.
If you're going to compare apples to apples, the top marginal tax rates are about 45-50%+ in Canada (http://www.aurorainternational.net/Maximum_Personal_Marginal...) - and given the estate taxes in the US apply to anyone inheriting above a million, it's relatively equivalent for those people while it's considerably worse in Canada for everyone else given that considerably more people inherit less than a million. Another point of comparison - highest marginal tax rates start at 126K (Canadian) while you have to make over 370K USD to start getting charged the highest marginal tax rates.
Addendum - re: gifts - http://en.wikipedia.org/wiki/Estate_tax_in_the_United_States - "the gift tax prevents avoidance of the estate tax should a person want to give away his/her estate."