DHL courier service is world-wide and popular at China, due to it's faster/safer/cover more areas. Usually transit time is 3-4 work days to USA/EU, 5-6 days to South US.
bout UPS courier service:
UPS is one of the four international express companies, it owns all-cargo aircrafts all over the world and provide a series express service.
about FEDEX courier service:
Federal Express (FedEx) is one of the world's largest express transportation companies, providing services over 220 countries and areas, reliable, growing fast. It's good for transporting high-value, timeliness shipments, has priority (IP) and Economy (IE) two kinds of service.