shouldn't hf test the devices before shipping? the fault rate seems so high! and I wonder how long the RMA takes?
We do test the devices before shipping. But vendor implementation of the USB spec varies. If your laptop doesn't work, try your desktop.
A high quality PCIE/PCI USB adapter often helps.
If the boards are having trouble running in a chain, try running one or two independently and isolating the problematic board on its own USB and cgminer instance.
Always use the latest firmware (0.4) and cgminer (4.1.0).