I ordered some cables from this online store in the states (I live in Canada) the cost in goods was $30 for both packages.
The first time I ordered the cables I was in a rush so I used FedEx air 2 day, it cost me about $26 in shipping and arrived in two days. Total 30+21= $51 CND
The second time that I ordered cables from this store I wasn’t in a rush and decided to use USP ground shipping instead of FedEx for $13. A savings of $8 or so I thought. When it I arrived at my door a 10 days later I was asked to pay $40 in brokerage fees (COD) on top of the $13 in shipping fees that i already paid. Total: 30+13+40 = $83 CND. I refused delivery.
$53 in shipping and brokerage fees from UPS,
$51 for shipping and the product from FedEX.
In this case it would be cheaper for me to make a new order from the store and get FedEx to ship it then it would be for me to accept the USP shipment and pay the brokerage fees, and thats exactly what I did.
Two weeks later I get a call from UPS asking why I refused delivery. I told them my story and how its cheaper for me to make the purchase again then it is to pay for outrageousness brokerage fees that they where charging and ended the conversation with ‘Why would anyone choose to use USP over FedEx?’
They asked me to pay for the current ($40) brokerage fees and additional ($13) shipping it back to me on top of the money I already spent on shipping the first time. For a total of 40+13+13= $66 CND due. I refused.
They told me that I would not get package delivered and it would be returned to sender. Prefrect maybe I can get the seller to ship me the products via FedEx this time and it would still save me $45 (=$66-$21) in the end.
Last time I ever use USP.

We use UPS/FedEx/Purolator at work.
When preparing a shipment, the shipper has the option of choosing who is billed for the duties: the sender, the receiver, or a third party.
So it’s not actually UPS or FedEx who is at fault or you paying the duties, but the shipping at the policies of the store you purchased from.
If the sender is paying for the duties at the time of the shipping, then this cost gets rolled into the total amount you pay for shipping. If the sender does not get billed for the duties, then you may have to pay brokerage fees when you receive your shipment.
Or something like that… It can happen with either company, though. FedEx has called us a few times to advise their were clearing goods through customs at no charge, so FedEx is sometime a better choice.