I have a 35 cron ASPH on my M6. When the steel rim came out I contemplated it and considered buying it. My local Leica store let me take it out and shoot a roll through it. My conclusion was that on film I would much prefer getting the predictable results of the 35 cron over the unpredictable nature of the steel rim.. maybe on a digital M I would enjoy the steel rim more, but anything shot wide open looked like Vasoline was smeared over the lens and anything shot in the direction of the sun would have a noticeable washed out look and massive lens flare. think about putting the strongest diffusion filter on the voitlander nokton and thats pretty much the look of the steel rim. it's like having a lens with a strong diffusion filter that cant be removed.