For every system both XLR and SE need to be tried. When I move I’ll try XLR out of my DAC again. It might be better in the new place, only one way to find out.
The case for single ended.
SE is a more pure signal. Balanced will always have a bit of distortion.
What make balanced so good at rejecting noise is also where this distortion comes from. I’m simplifying the process a little. The end result is still the same. Balanced works by sending two identical signals down the cable. When they get to the SE component (or ZBIT) a circuit compares the two signals. Anything that isn’t identical gets thrown away. This is great for getting rid of interference and other noise the cable picks up along the way. However no circuit is perfect, some of the original signal will be thrown away too.
My guess why many people prefer balanced XLR over SE is due to the extra gain.
Galen Gareis cable designer for Belden and ICONOCLAST discusses XLR vs RCA.
https://forum.psaudio.com/t/rca-vs-xlr/14787/19As for the transformer magic... I love it! That is why I have a transformer based volume control.