It is interesting that he listened in three systems of increasing quality, and the positive difference of the SL became increasingly apparent. His final reference system was not really all that fine though. But seriously, who would be buying a filter who didn't have at least the level of quality of his 3rd setup anyways?
I tried a Muon between my EtherRegen and exaSound Playpoint and found it had a slightly negative impact. Transients were rounded a bit and highs smoothed, not my cup of tea. I did like the Muon upstream, between my modem and router.
He also tested the English Electric EE1 recently and claims to prefer the SmoothLAN in this price segment.
I have one on order just wish Stack Audio will ship it!
The only LAN filter I have is the Waversa EXT-1. It is the opposite of relaxed, it induces a huge wall of sound in my system that comes across as exciting, but a bit artificial. I found the best place for it was filtering the NAS, which stores my local music/video files.