This set never made it to a stage before being returned. I wanted a convenient radio link for an acoustic electric to be rid of the dangling cable. But first and foremost for me with ANY accessories, pedals, whatever, is sonic fidelity.
Like ALL radio systems the sound takes on a harder edge than a cable, perhaps due to buffers in the circuit - much like Boss FX pedals when in bypass mode. Piezo pickup equipped acoustic guitars already have a hard time sounding sweet and this radio just aggravates that problem. Not this radio in particular, I hasten to add, because I have A/B'd it with quite a few. But they are all the same.
However, there is another issue with these very convenient plug-in dongles. This is the second one I tried and it has the same problem as the first one. Because the dongle has more mass than a jack plug on a cable, it is susceptible to causing really nasty 'dirty connection' type noise periodically as the dongle jack rotates or moves in the jack socket.
It may well be that the jack socket Gretsch fitted has a very slightly larger diameter than all others, thus permitting movement that is sufficient to occasionally and momentarily break the circuit in the same way a dirty connection would.
I prefer to use a strap mounted transmitter with a normal jack plug.