USPS is the best shipping option if it's coming to Canada. It's always the best shipping price, you don't get raped on the brokerage fees, and the service has been extremely reliable (at least from my experience).
I avoid UPS like the plague. They charge exorbitant rates for the brokerage fees, and even one time tried to charge me a fee to collect their fees! Since then, I have instituted a policy whereby I have a "Returning the Digital Signature Device Fee" that I have to charge the UPS driver. Unfortunately, I'm not able to waive the fee since it's policy. My hands are tied.
To all vendors, please, please, please! always have a USPS shipping option for shipments to Canada!