Thanks for the update. I was orignally looking at the Ref 5 and Ref 9 but now these options are gone since the 1704 chips are obsolete and depleted. Do you ever have to worry about the NGB-1's top-end being overly detailed/sharp/prominent as this could be the case for the ES9018 chipset if not partnered right with the right gears? Do you consider the NFB-1 musical and smooth still?
Lastly, in my experience, I found that burning in gears with the Isotek burn in CD greatly speed up the burn-in process for gears, cables, speakers, etc...