Thanks for the responses, it seems like either of them would be safe bets!
I don't know if this should be in another question, but does anyone know if the advertised performance, ie 384khz at 32 bit depth on USB is attainable on USB 2? I have space to put a USB 3 card on my mobo, I suspect it probably needs USB 3, but I've only got 2 on this box.