NBS vs MIT

Let me know what set up do you have.  Front end, dac transport??  Sacd or redbook?? 

Proceed transport
Theta gen va DAC
Spectral dmc 20 preamp
Spectral dma 90

I would look into the nbs black label.  I would stay away from monitor series ( monitor series was for sacd, or music servers).. i would take the black label over the Mit cables.  

I would get the digital cable from someone who actually understands how to properly build a digital cable -  Chris Sommovigo 's Black Cat Cable springs to mind.

https://blackcatcable.com/collections/redlevel

BTW - I had great results with Genesis Digital Lens between my Theta transport and Theta Gen Va DAC back in the days. I believe you can get one used for $300-$400 nowadays. It greatly improves the performance of the Gen Va, which is very sensitive to jitter.