Simon, good is an understatement
In general mid range so much more defined, more air around the soundstage (stretches further out) and so much more detail in terms of separation, vocals bang centre, backing vocalists now very clear and separated all with a vice like PRaT. Bass again another layer peeled away to reveal more detail to the baseline and different strands. Bass is also going allot deeper, tried a very known to me complex bassline track, first time hearing parts of the bassline where it would get muddled or tripped up as the bassline change direction, now it lays it out with ease, sublime.
Most impressed with the midrange detail uncovered, akin to much greater system changes. Vocals are so sweet now, bar far the midrange is where it all happening at the moment (assume a bit of settle in and things will improve). Instruments that were single strand and dull are now dynamic multi stranded texture. Subtle very subtle instruments in the background are now audible in some cases maybe a little more than I would like, but thats why I went Naim the ability to do PRaT, unravelling complex tunes with ease.
Versus my prior Netgear 105, night and day significant improvement. The Netgear versus my Sky router was a noticeable improvement with the Muso, but versus the Cisco, the Netgear sounds muffled, veiled and confused.
I purposely avoided reading other posters findings in detail, so as not to pre judge.
Oh the IEC is poor but for now will stay, one change at a time so sure where the change originates. Oh and my setup is for living room aesthetics, so router on it's side, cables all stuff behind tv cabinet.
Had fun talking to my brother IT guru as was unsure where to plug the wires, got the whats wrong with the Netgear, it's a switch man, you not going all hifi crazy again (recalls my obsession 20 yrs ago).
I'm a firm believer of squeezing the most out of a setup before box upgrades and this switch delivers.
Lastly midrange I say it again as so major, dare I say this is closing the WAV 24 bit via USB. Some say chill and buy more music, but get step changes like this and you end up listening to the same collection in a new light.
Acknowledge sound is a little clinical and forward, that may settle but for me the Naim sound was always clinical which I liked.