My pets couldn't care less.
There are some differences in the image qualities between the Quattro and the Merrill... some good and some bad differences.
The Merrill images may have more micro-contrasts than the Quattro fresh out of the SPP6, tweaking the raw processing parameters can reduce most of the differences in micro-contrasts in the Quattro images. This and the much better low light AF performance and other advantages listed in my review tend to swing my vote towards the Quattro.
The true test is that if I have to rush off to shoot something and I have the both DP2M and DP2Q (and I do) side by side on the table, which would I grab to take along? I would have to say the DP2Q because it is just more versatile and could cover me in more situations than the DP2M could during a shoot.