The 35mm Curtagon is good, but not great. A bit soft at wider apertures, but the colour rendition is excellent in keeping with other Schneiders. Agree that the Xenon is excellent, as is the Rodenstock Xsarex. Beautiful camera to use and look at though, and agree that the Tele-Arton could be better, not so much the image quality, but the thing doesn't focus near close enough for a portrait lens.
I think that the 28mm Curtagon is a better lens, slow at F4, but great colour.
I had my Tele-Arton adapted to my Bessamatic because I couldn't find a 90mm for it. BTW, the 35mm Skoparex from the Bessamatic is a superb lens and I think that they can be fitted to the Retinas quite easily.