Although it sounds a little better than the squeezebox Duet, I just sold my Onkyo ND S1 because I wanted access to my computer which offers more music than what was on my iPod.I had Steve Sank, of Talking Dog Transducer Company in Tucson (30 years experience) mod both my Onkyo and my Duet. The Duet modified, sounds a little less dynamic and detailed although a touch warmer than the Onkyo (which is also warm but has better seperation of instruments). I improved the sound even more with a laboratory grade lambda regulated linear power supply purchased cheaply on ebay.
The person who bought my Onkyo idock confirmed what I already knew, and said the Onkyo ND S1 kicked the teeth out of the Wadia sound wise. He was pleasantly surprised. I also had the Cambridge idock and it sounded rather lackluster in comparison to the Onkyo also - unless you like a very soft non distinct sound.
Again, you can purchase an Onkyo idock at half the price and twice the sound of the Wadia idock on ebay from Japan with a universal power supply that works fine in the USA for around $200.