I sold my Stream-IF today for a lot less than the cost of the Nagra. It looks identical to the Nagra EXCEPT the Nagra has 3 outputs, Plink, SPDIF, and USB.
The latest PDB streamer that costs $3k has Plink and USB.
The prior version that I sold, PDB Stream-IF, has Plink and SPDIF.
Nagra just put USB and SPDIF together and charged more.