In testing it with the cheaper FMC, I would say the audible difference was marginal, but the overall quality seemed more refined.
A few years ago I added a switch with fiber and an EtherRegen+LPS and created the 'fiber bridge' from my noisy equipment closet (switch location) to my clean audio room (all equipment on dedicated AC line, no switching power supplies). I thought this offered a nice improvement (more detail, blacker background, etc.) for the $.
I then tried swapping the EtherRegen for a non audiophile ~$100 fiber converter and didn't really notice a difference, so sold the EtherRegen. I'm still using the cheaper converter today into my Bricasti M5 with great results. I don't know if the M5 plays a big part or not in making the fiber conversion not something I had to spend decent $ on.
What I do find interesting is I added an LPS to my Roon Server which is directly connected into my switch (dirty side of bridge) and it made a significant improvement to my ears. I wasn't expecting power/noise-reduction changes on the dirty side of the bridge to make a difference. That has me tempted to now try a LPS on my switch, not that I really want to buy another LPS :( Some folks may call this expectation bias but I already had a dual output LPS with an unused output and with no expectations for improvement, I really just think it sounds better for some reason...