Marc, it was nice to meet you. Your ISO 1250 photo looks pretty good. The 1250 photos I took show a good bit of noise, but they have a grain look to it and may look good in B&W or other situations.
Steve, the tattoo photo was at ISO 320 with an off camera flash. That particular photo has a gritty look to it that I like. I am not sure why it looks different - maybe it was the flash or the man's complexion. Fortunately, you will get a chance to see the S2 capabilities first hand on Dec. 3.
Additional comments about focusing.
Speed and Accuracy - I found the autofocus S2 to be very accurate. I didn't loose a single shot due to missed focus point. I also found the focus speed to be acceptable, but not dSLR quick. Focus accuracy is more important than dSLR speed to me. Of course, I would love to have dSLR speed along with high accuracy.
Single Focus Point - The fact that the S2 only has a single center focus point doesn't bother me at all. I shoot sports and wildlife with my dSLRs and always use the center point only (simply because it is the most accurate and fastest).
Focus Tracking - I didn't get a chance to specifically test the S2's ability to track focus of a moving subjects. I don't expect the S2 to have dSLR focus tracking capability. However, I do expect it to be able to keep up with a person walking. I wished I had tried that.
Manual Focus - Simply put, manual focus is a dream on the S2. The viewfinder is big, bright, and offers good feedback for manual focus. The 70mm and 180mm lenses I used were both a pleasure to manual focus with the right amount of focus drag/tension/feel and a comfortable focus throw.
I have to remind myself that the S2 is not yet released and it is reasonable to expect Leica to improve the firmware between now and then. I expect the S2 to be better in some performance areas when it is released for sale than it is now. Another improvement will come with the release of camera specific profiles for the raw conversion software.
I am adding another photo which shows (at least to me) the S2 is capable of quick enough autofocus and at least some focus tracking. The street car in the photo caught me by surprise. It came up behind me and by the time I heard it and turned around it was already even pretty much even with me. I raised the camera, pressed the rear focus button, and fired the shutter as I was panning to keep up with the street car. The photo is far from perfect, but it came out pretty good considering the quick moment in which it occurred.
70mm, 1/60th sec, f4.0, ISO 320
Crop
Edit: corrected typo