Over on LensRentals.com, they've posted a
rather interesting 50mm shoot-out which compares a variety of 50mm lenses... From SLR to M mount, covering Canon, Nikon, Leica, Zeiss, Voigtländer and a few more. A total of 19 lenses.
What's interesting to note is just how well the Leica Summilux-M 50mm f/1.4 ASPH performs as compared to other lenses/bodies. It's easily the best performing lens out of nearly 20 lenses (on average)! Of course, some of this may be due to the lack of an AA sensor in the M9 (though it competes against higher MP count bodies with an AA filter) - but regardless... Rather impressive.
I do have to say, the 50 'Lux ASPH is a killer lens by most any measure. We'll be doing a full review of it here soon - stay tuned!
Maybe we'll do an M8 to Canon 1D Mark IIn w/50mm f/1.2L comparison - with the M8 having 10MP and the Canon 8MP, it might level the playing field a little.