I was lucky enough to get an M9 within a few days of the release, and have now shot over 3000 frames with it. I agree with most of what Michael says in his review, but would add a couple of additional points.
1. The M9 manual says no collapsible lenses can be used with the M9, however I've had written confirmation from Leica that the recently discontinued 50mm Elmar-M can be used. This further adds to the M9's appeal as delivering the highest possible quality from a truly "pocketable" camera.
2. A number of reviewers have commented on the studio based S2 being weather sealed, while the M9 is not. This struck a chord as I abandoned the M8 when it failed on a few occasions in arduous but not extreme conditions. The first time was in Karachi in the sweltering heat and humidity just before the monsoon arrived. The M8 died, switching on and off and removing and replacing the battery failed to revive it. But after a few hours in an air-conditioned room it sprang back into life. After suffering the same experience on two or three subsequent occasions I threw in the towel and sold the camera. I took the M9 (with the original 0.922 firmware) on a trip to Sorrento and was out in a rain shower, the camera got wet but not excessively so, however it wouldn't power up. Luckily this time the problem was very temporary, and removing and replacing the battery brought it back to life. There have been no further failures despite being subsequently used in the rain.
3. Michael commented that he only saw one example of moire, unfortunately I'm seeing many more. The first, and least serious, category is with moire being visible on the camera's viewing screen but not in the downloaded file. This is very common (and still persists with the latest 1.022 firmware), it can be an inconvenience because sometimes you're tempted to retake the shot, but at least it's not a permanent impairment to the image. The second category is tiny incidences of blue/yellow artifact pattern (I'm classifying it moire, it may be something else) that virtually disappears in even fairly large prints. I've included a full frame and a 100% detail below that illustrates the scale and nature of this problem. Then there's the traditional moire problem often associated with fabrics, some have been easy to deal with but some have so far proven more intractable. I don't want to overstate this issue, out of 3000 shots I've lost only one frame to moire, and that may be the result of lack of processing skill on my part rather than the severity of the problem, however I can find thirty or forty M9 frames where moire is present to one degree or another.
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4. The final point I'd make is that sensor dust is proving to be a reasonably serious issue with the M9. I've cleaned the sensor once, but within a thousand frames it's been necessary to "spot" about ten to fifteen dust specs per shot. With a my Phase One back sensor cleaning is easy, and with my current model Canons it's hardly ever needed. But the M9 is like stepping back a few years in the history of digital photography! Not a show stopper, but neither is it completely trivial.
5. The wider metering capture area comes as a shock (after many years of Leica use), it seems a lot broader on the M9 than the M8 and M7. It's probably appropriate for auto exposure, but makes more considered exposure setting slightly more complicated.
6. The return to 1m frame lines is IMO a retrograde step, and Leica's explanation (that M9 shots won't be enlarged as much as M8 shots) seems plain daft.
Overall I'm delighted with the M9, if it can maintain a reasonable degree of operational robustness then I'll put up with a few little foibles to enjoy the unique combination of exquisite, filmic image quality in an exceptionally compact package. It's also easy to see how the "M" lineage can develop from here, and I look forward to a healthy Leica lineage of M10's and beyond, that will challenge the optics with yet more pixels and maybe other enhancements like camera based anti-shake, better weather proofing, and a self cleaning sensor!
