K330 - You will wait until the cows come home. Async USB interfaces are only as good as the designs, just like anything else. Some are worse than other interfaces, but the best ones leave even the best CD transports in the dust.
Metrum Octave or Audio GD are safe bets. The Synchro-Mesh has a money-back guarantee. Much simpler than going the USB route and achieves the same performance. Only drawback is that it does not support native playback. If you want the 192 file to play as it was recorded, the SM is not for you. If you mostly do 44.1, it is perfect.
Steve N.
Empirical Audio