Most people use UPS because their rate is cheaper to start with. BUT WAIT, that is because they are talking about the UPS Standard Services (i.e. Ground Services). For this services, the receiving party has to pay all brokerage fee base on a fixed rate scale of the actual declared value.
If you use UPS AIR services, their rate will be roughly about the same as Fedex, and the receiving party will not have to pay any brokerage fee. BUT their customer services is another story.
Fedex is actually the same. If you use Fedex Ground between USA and Canada, Fedex will charge brokerage as well.
It is just that Fedex's default service is AIR, while UPS's default service is GROUND.
Hope this help.