Sorry to divert a bit, and also sorry if I'm wrong here, but I always thought the thing that differentiated firewire from USB 1 and 2 is the fact that the firewire protocol guarantee's synchronisation of video and audio data being streamed, whereas USB protocols don't. I've just googled "usb 3" to see whether there's any suggestion that the USB protocol has been enhanced to provide the same guarantee of synchronisation as firewire, and I haven't hit anything definitive. Therefore I'm not yet convinced that USB3 will make firewire obsolete. Would make life easier though, one less interface to worry about.
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John Allcock