Scrith -- It would be computer-dependent. USB relies significantly on processing by the cpu and its associated chipset on the motherboard. I would expect that a modern well-tuned computer with adequate memory will have no problems, but a computer which is bloated (as many are) with large numbers of useless background processes, and is configured with too little memory to support them optimally, and/or is running resource-hogging Vista, or is old and does not have typical contemporary computing horsepower, will have problems.
Firewire, in contrast, shifts most of the processing associated with the interface to the interface chip itself, and guarantees that the data rate will never fall below a certain amount (which was chosen to assure that the DV format (Digital Video, for which the data rate is much higher than for audio) could be transferred without interruption).
In response to your closing comment, btw, in my case I did not claim that "USB can't support 24/96," I just said that I would not be surprised if it (USB1.1 specifically) were to intermittently break up. I should have added to that statement the phrase "depending on the computer."
Regards,
-- Al