The 38 biogon is totally useless on a digital back of more the 1,5 Mp. I tried it years ago with a CFV but it was horribly bad, but not to say totally unexpected.
I use my 903SWC with Sinar 75LV DB, and the pictures are stunning! I also compared it with Alpa's Schneider 35XL digitar and Hasselblad 40IF, and 40IF is the sharpest one. 38 Biogon is as sharp as 40IF in center, but shows softness at corners. 35XL digitar is still not as sharp as 38 Biogon on 75LV. In terms of color fringing, 38 Biogon is the worst, but it can be corrected. 38 Biogon also has least distortion, which is great for architecture.
The one listed on eBay is a redesigned 38 Biogon used on 905SWC. It uses environmentally friendly glass and is less attractive.