So, is the concensus that RCA termination or BNC termination is equally reliable for transmission of digital audio (say between transport and DAC)??? Or are there quantifiable differences between the two type of connectors?
I don't think it's readily quantifiable. The degree of sensitivity to impedance mismatch would be dependent, among other things, on the risetimes and falltimes of the digital pulses, which are not specified and probably differ among different components; the length of the cable; the amount of mismatch at both ends; and other factors. And the differences that the connectors make (such as the effects that impedance mismatch might have on jitter, resulting from its effects on waveform quality) might be overshadowed by other differences between the components being compared.
The best guide is probably just reading about other people's experiences with the particular components, and if possible auditioning them yourself.
Regards,
-- Al