They’ve also used DHL in the past. I’m not sure if they choose based on price/location or if they switched from DHL to FedEx since the last time I ordered.
(I know they didn’t use FedEx then, because FedEx wouldn’t deliver where I lived, and I wouldn’t have ordered from Apple if they used FedEx. Why FedEx wouldn’t deliver where I lived, and how we found that out, is a lengthy rant not suited for a Fluther post.)