From an operations point of view, Gulfstream 650 has a performance range of 14 hours non-stop even under part 135 executions. This is an excellent performance range for ultra long haul flights such as from USA to China.
14 hours non stop performance means should there be any unforeseen route changes due to weather disruptions or air traffic tower requirements, G650 has more flexibility to accommodate these last-minute route changes compares to other models that are restricted by performance range.
Every aircraft is designed for its specific market position in the world. Gulfstream 650 is perfectly suitable for a direct flight between the USA and China.