A 24x36 frame needs a x8 enlargement for a 8x12 (aprox. A4 print).
Whether the sensor and lens resolve 40 lp/mm we will get 40/8 = 5lp/mm of real detail in the print. Just the amount of detail the human eye can resolve, at best, at optimum distance (25cm or more, depending on age).
For a A3 print (12x16, aprox) and 5 lp/mm of real detail the sensor (film) need to resolve 80 lp/mm. There is no full frame digital camera with this resolution power (I think a 22MP full frame camera would be necessary). Only medium format cameras, mostly due to the smaller enlargement factor, can reach the necessary resolution for those prints.
These requirements are increased for a cropped sensor. The M8 sensor has a crop factor of 1,33, and therefore 40x1,33 = 53 lp/mm and 80x1,33 = 106 lp/mm should be resolved in order to have 5lp/mm of real detail in those prints (A4 and A3).
The 74 lp/mm of maximun theoretical resolution (Nyquist limit) of the M8 sensor -but less than that number of real maximum resolution-, means that the M8 is capable of gorgeous A4 prints, but other cameras actually in the market will provide visibly better prints at A3 sizes or bigger (I am thinking on the Canon 1Ds Mark II and Canon 5D, due to the bigger picture size -number of pixels- and smaller enlargement factor). I think the M8 could be comparable with a Canon 1Ds, in terms of detail resolved on paper.
The image quality will be very good, due to the optics, the abscense of low-pass filter and the (big) size of the sensor. I try to say that 10MP in the M8 are not like 10MP in other cameras with inferior lenses and smaller sensors. However, the full frame cameras with more pixels, specially if they work with good lenses, will provide higher resolution on paper. Color rendition, contrast, distortions and fingerprint of the lenses are another history... Leica lenses are hard contenders here.
Erwin Puts' comments are fair, but he was using a camera with unfinished firmware. I don't expect such differences between the 5D and the M8.
