Canada is much more lenient on pot. Medical marijuana is legal, and pot laws are sometimes blatantly ignored (such as the cannabis cafés which operated in Vancouver for some time). You're highly unlikely to face any jail time for possession, in fact you'd probably get off with a warning or a fine at most, from what I hear. And there is a strong movement for outright legalization. A friend of mine went to a legalization rally on Parliament Hill where hundreds of people were smoking right in front of the cops, in front of Parliament (nobody was punished)! Also, Canadians in general are more accepting of weed, and are thus less likely to rat you out if they catch you.

Plus, the bud up there is soooooo good. Shwag is almost unheard of, and the dankest strains are abundant.