I have used all three transfer methods. I now use USB because all music is upsampled to DSD256 using a dedicated high power music server into the HoloAudio May KTE DAC.
Optical has to be converted to an electrical signal so quality depends on what 15¢ part is used. Optical is a fiber glass version of SPDIF so it adds even more jitter than Coax.
Coaxial is always a solid choice for 44.1 and 96 kHz recordings.
High-res almost always requires USB and a lot of times a driver needs to be installed too.
A lot more technical stuff that can be done to a digital signal. The HoloAudio May KTE has a lot of USB enhancements and other technical stuff, click on the link for a deeper description
https://www.kitsunehifi.com/product/holo-audio-may-dac/"The May DAC has the new and exclusive USB Enhanced module (L2 and KTE ONLY) which has our FPGA with the new Titanis 2.0 and custom firmware to improve USB Eye Pattern and reduce latency to near zero as well as reduce jitter to very very low levels. The USB module has completely new code written to optimize performance and reduce latency significantly. Low frequency performance (-40db) is also improved. The “enhanced” USB xmos module is twice as powerful/capable as the one that is used in the Spring2."
