USB connection issues?

In response to a recent post on the proposed use of USB as a possible board interconnection system, reader Eric bemoaned, “I am not sure about this. I have not had good luck using USB in 24/7 applications. It seems that it drops out from time to time and the OS does not see the USB device.” Obviously, any intermittent performance is unacceptable in deeply embedded applications and would disqualify USB as a multiboard interconnection medium. If you have any problems or success with continuous communications over USB, why not post your experience to either help Eric solve his issues or stop StackableUSB in its tracks?