I have been running my Atom/Iotas via WiFi for a couple of months as the router is several rooms away. I have been very happy with the sound (some (now resolved) room/acoustics issues notwithstanding), but I have been intrigued as to what different there would be if I connected the Atom directly to the router.
To find out I bought a 30m CAT6 network cable, which I traipsed around the house (much to the 'amusement' of my wife) and this morning plugged it into the Atom.
Well, there was a definite difference. For a start speed. With WiFi I tapped a track on the iPad and a few seconds later (sometimes quite a few seconds later) it would start to play. With the wire it is instant, no delay - I like it.
But also the sound is quite different, more so than I thought it would be. This might seem odd but the soundstage seemed tighter, more compact - and not necessarily in a good way. It was also quieter - I know that Norah Jones' 'Sinkin' Soon' needs to be on 48, but now it needs to be on 55). However, the performance was more solid, stable. If the trombone was just 'there', it stayed just 'there' and it was very clear that it was 'there', nothing vague about it (there is probably a HiFi term for that). The clarity also seemed better and despite the whole performance seeming to lose scale, it was punchier and had more rhythm. It was more enjoyable.
The reason I am confident that these differences are real is that I have been playing around with set up a lot in the past few weeks and I have been using the same 15 or so tracks and so I have developed a good sense of what they should sound like or have previously have sounded.
I did intend to give it a 15 or 20 minute blast just to see if there were any really obvious differences as I had other things to do today. However, I was listening for 2 hours - which I think is a good sign.
I still need to do some experimentation, but I think having a wired connection is definitely a good thing, which I guess is logical, but WiFi also works well.