I have bought one "Rolleigon" lens (a 50mm) that had mechanical issues and I had to return it. My camera came with an 80mm that was in very good shape and has worked without issues, and I also bought a 150mm that was cosmetically rough but has worked fine. That's not enough to make any kind of real determination, but thats my experience. Also, my lenses are older lense that work correctly with the SLX and 6006 camera, not the later lenses that work with the 6008 line, but I expect quality is similar on both.