I haven't tried it yet, but iFi also just came out with a $300 "LAN iPurifier Pro." It does support Gig internet, which can be useful for 100Mbps+ video streams. I'll eventually compare it to my TP Link optical converter boxes.
Recently, I did try two iFi LAN iSilencers in the stereo system, which I thought helped. I put one between the multi-gig switch and first converter, and the other between the second converter and streamer. And, on the theater system, I also liked the picture improvement that an iSilencer made with the Apple TV.