It really depends on what program you want to specialize in. Each department has their own specialty.
In terms of overall rankings on econ departments, all three are similarly ranked, although U of Guelph does come out ahead. Check out http://ideas.repec.org/top/top.canada.html for more rankings. Messing around their website will also give you rankings in specific disciplines, but these programs not being in the top may not show up on the list.
I would say do your research and learn about the specific specialties in each program and see there are any professors you would like to work with. I hope this post is in time for your deadlines.