Anyone tried fiber into EtherRegen SFP?

Putting a 2nd-hand EtherRegen before my Innuos Zenith Mk3 has probably been the single best upgrade I've made.  Like most others' experiences, the shift away from a digital sound has been palpable.

I'm feeding the ER directly from my Netgear Orbi mesh satellite through a Wireworld Starlight ethernet cable.  I was wondering, however, if anyone has experienced significant gains from feeding the ER with fiber into its SFP port? 

I did assume initially that as the ER is a regenerator the quality of the input shouldn't matter that much.  But as I saw another jump when upgrading the ER's input cable it's set me to wondering about optical.