How much better is direct BNC vs adapter


Just got my new Chord CuTest and it uses BNC coax and my Bluesound Node2 uses RCA. So I am currently using a RCA to BNC adapter with. Kimber AGDL RCA/RCA cable. I am considering buying a new cable and have it terminated RCA/BNC, but wanted some opinions from fellow Audio-goners, is it worth any further concern  to eliminate the adapter. 
2nd part to this question, is what cable under 500.00 would you pick?

Thank you in advance
128x128theo
I have a Nordost Silver Shadow 2 which is terminated BNC on both ends, NAIM server is BNC but Aesthetix Pandora is SPDIF coax, so I use the adapter....IT sounds fantastic and is quite close to my reference AudioQuest Eagle eye which runs adapter free....

the provided Nordost adapter works fine.

Ron Buffington here on Audiogon sells the Silver Shadow II, contact him for a quote...a fantastic cable IMO
I used a bnc adapter for a digital set up from dac to transport and later bought the identical cable with the bnc connector installed by builder, as much as I wanted to hear a difference, I could not. I did have peace of mind on the matter and am sure there are some here with more acute hearing can detect a difference/improvement. A very good cable and for half of your budget is the Acoustic Zen MC2, give it a try. Happy listening.
Thank thank you both, for your responses. You have added to my belief that the adapter really isn’t hindering performance. I am curious to try a few different cables, I brought home a Cardas Clear, but the connector won’t go into the Node2. They have a little guard around the connection although I can use my Golden Ref’s on the analog outputs. And toolblue, I have plans to try the Acoustic Zen, recommended by The Cable Co, thru their lending library. 
Audio Engineer who participates in these forums sells a $275 BNC cable with RCA adaptors.  I purchased one a few months ago.  Beats the pants off RCA coax cables I have tried for twice the price.

Don't do BNC-RCA cable.  Use the BNC-BNC cable with a 75 ohm adapter, not 50 ohms.  For 99.9% of systems you will not hear any degradation with the adapter. You can get them at Markertek.com

Steve N.

Empirical Audio