I do not like the new Yahoo answers format used in the U.S.?

Yes.

I originally signed up on the US Y!A site. But lately I've been doing most of my answering on the Canadian one. I can tell you with confidence that your points are the same no matter which site you use, and getting Best Answers on any of them will count towards being a Top Contributor, and also this was a surprise to me, that answering questions on different international sites still counts towards being a Top Answerer (top 10 most Best Answers in a particular category on a particular Y!A site), in other words even Best Answers given on a different site count towards Top Answerer on the site one originally signed up on.

A slight correction to the answer above: yes, the points will go to your account and the BA's too. While you may make BA's on any of the international YA sites, they will only count in your home country - I for one am a German user who is more active on YA than on YC Germany, I have more BA's in some Yahoo product categories than some of the category leaders, but I will never show up in lists of the YA category leaders - only in the lists of my home country...:-)

edit: when I said "the answer above", I meant the 1st answer, just saying to avoid any confusion...

All your points go to your account for sure. I'm in different countries constantly and still get all my points. >3

The points will go to your account

but the best answer I believe will go towards the country you answered from