Originally Posted by Sean Setters
To elaborate further, the new PW units can do normal/HyperSync/high-speed sync or normal/high-speed sync or normal/HyperSync. For any of the modes that use high-speed sync, they can increase the usable light output of your flash, up to 1.8 stops better (camera-dependent). This is a prime reason why I have three Flex units on order, due to arrive on Monday.
I'll admit that I'm aware of the distance limits with the 580II flashes that I use, so I ordered two SuperClamps (to hold the Flex units on the stand away from the flash) and two OC-E3 cables to interconnect the goods, and picked up some ferrite cores at RadioShack today.