Out There On Its Own
How does the M9 compare with its competitors? It doesn't really have any. Epson hasn't expressed any interest in continuing to develop its RD line of digital rangefinders, and we've yet to see a digital Voigtländer.
If you're debating between the M9 and a full-frame DSLR, such as the Sony Alpha 850 or a pro model closer to the Leica's price range, such as the new Nikon D3S, there's really no comparison. They're completely different tools for completely different styles of photographer. We don't categorize the M9 as a pro model-think of it as the ultimate (deep-pocketed) enthusiast's camera.
Suffice it to say, Leica finally has a digital rangefinder that should please most of its loyalists. And finally offers them a painless alternative to film.