For sound quality, the recommended version is the original 'Audiolab' branded version (v0.90). The more recent versions which John Westlake released fix a few bugs (e.g. filter selection when the input is not set to USB), and add some very nice features, but, as recognized by John, do not sound quite as good if one is picky... For input renaming, etc. I believe that the A.10 version was the best compromise, but your mileage may vary...