Ivor Mantanle wrote about the Werra in the 27 March 2004 edition of Amateur Photographer (a U.K. publication). A very good piece, as usual. The Werra uses true interchangeable lenses with a behind-the-lens Prestor leaf shutter.
Some of the later shutters offered a top speed of 1/750, quite remarkable given that most leaf shutters topped out at 1/500. I believe one or two Copals hit 1/1000, but I can't remember which camera that was.
I have a very nice Werra 3 that I bought last week. The camera is a nice small size, and the design is very unique with a clean top deck and very few visible controls. I just ran a roll of Orwo through it -- haven't yet processed it.
Mr. Mantanle had an interesting story about the Werra. The story is that after the Kiev factory had been set up in the Ukraine, some of the German engineers were allowed to return to Germany. Carl Zeiss Jena, he wrote, now had an abundance of people, and some were allowed to work on side projects. The Werra is the result.
The rangefinder system is unique in that there is no secondary image. The central image overlays the primary viewfinder, and when focusing, you must align the central image with the surrounding image. It's not a coincidence rangefinder. That means horizontal and vertical alignment of the rangefinder is very critical with this camera.
Great little camera, and if you ever disassemble one, you can tell that this is a camera that was designed by engineers first and not with easy of assembly as a primary goal.