BNC or OPTICAL links?

"BNC" is not a "link". It's a connector for the S/PDIF interface.

Also, your question as stated can not be answered.
It is like asking: "What's better, cream sauce or barbeque sauce?"
For what?
Yes, people will answer it, and will have no basis for doing so except limited
personal experience and no understanding to back it up.

If a dealer answers that question, and makes a recommendation with only that info, RUN.

Using WADIA (ATT)-> WADIA ATT)? ATT is best.
That's one of the few mfr's I can say that about.
In MOST cases coax is a better choice, and AES/EBU is a step beyond that
(as is I2Se and I3W3), but, that can't be recommended for you based on the info you have provided.

Rephrase your question. Include the components you are considering and the inputs/outputs they offer. With THAT info a recommendation can be made. BTW, if this was analog gear, we would need to know what you have in the rest of your system, what is you like, don't like, and/or want to change/improve with it before any experienced, and HONEST recommendation could be made.
Lastly, keep this in mind when talking to "NET dealers", that many of them have never heard, and often have never even SEEN much of the gear they sell (we refer to them as "box dealers").

brian@hello.lt

I have found optical cables (ST) to sound softer and less focused than coaxial 75-Ohm BNC cables. As always it depends on your gear. Try both side-by-side if you can.

Bravo for Brian!!

Hi brian:you are correct,i placed the add before running to work and should have included more info,so here it is.
I'm running a coax type spdif cable from my transport to jitter attenuator(it doesn't have bnc or xlr)and the chronos jitter attenuator is also splitting the digital signal into two resaudio quantum dacs in balanced mode,currently i'm using a pair on bnc's cable and was wondering if optical att format will be better,thanks.AL