I had mine for about 2 weeks now and it sounds amazing. Compared it to several other DACs, both somewhat cheaper and in the same range. Although the W4S was also very good, the Wadia has a soundsignature which best matches my taste.
I did, however, have some problems with my unit. One particular problem is that after some changing of the inputs, the soundvolume is fixed, and at a pretty high level at that. Another problem is that after some use, the volume is just 'gone'. The headphone output is _way_ too high. But my dealer came through and is sending me a new one. Apparently Wadia is aware of (some of) these problems and an upgrade is available. It consists of a new firmware, but also some new hardware as I understand it.