I tried using it with my DPA 4099 condenser mic that is attached to my guitarron (acoustic bass guitar). There was a very loud high pitched noise when the XVIVE U3C transmitter was directly connected to the DPAs XLR connector. With an XLR cable in between them the noise was somewhat lessened, but still clearly audible. I have to keep them quite far from each other to eliminate the noise, which of course defeats the purpose of going wireless in the first place.
According to XVIVE this is due to interference from the amp in the DPA connector. But on the other hand the noise goes away if I hold my hand around the connector and transmitter, so I'm still suspecting that it might be grounding issue. Nevertheless, it was really surprising to me that it won't work together with such a well-known and respected brand of microphones.
So even though the XVIVE U3C is really easy to use and has a great form factor, it turned out to be useless to me in the end.