i just posted this over at the leica forum, but maybe folks here are interested too. so here it is:
i did some low iso comparisms between D3x and M9 today, both at their respective base isos.. nikon 85 f1.4 and leica summicrom 90mm. NX 2 for NEFs and lightroom (GRRRRRRR!!!!!) for DNGs. out of the box the leica DNGs looked better, or rather more acute. this advantage faded when some moderate sharpening was applied to the nikon files and in the end i came to the impression that the D3x files have a clear resolution advantage (24mpx compared to 18mpx). it was an evenly illuminated scene, so i have no DR comparism to offer.
anyway, i shall keep the m9 but tomorrow i shall cancel my S2 preorder. in all honesty, i am disappointed by the conservative leica approach (yes, i did know it when i bought the M9). but the direct comparism to the D3x (and most likely also to the 5Dmark2) is kind of frustrating. it is like comparing a TGV trip to a vienna streetcar. and yes, sometimes streetcar trips are fun....but you arrive faster on the TGV.