I would like to have a camera with a mix of features of both cameras. From the MP, I really appreciate the top plate made of brass. If you ever saw a camera with a top plate completely covered with bubbles, you will agree with me. Personally, I don´t have any problems with the skin applied to the body (in fact, it is really enjoyable) nor the rewind button, although I like the style of the angled rewind lever.
However, this button may be slightly slower. I am still to realize how much slower it is. Also, the electronics seem to be updated and the mechanism is really smooth, with a different sound compared to the M6. From the M6, I like the black chrome finish. Yes, I believe that the black paint is more pleasing to the eye, but the black chrome is certainly more resistant. I also prefer its advance lever. For the rest, the camera is more or less the same.
P.S. Forgot to say that the MP viewfinder is clearer, with a slight blue tint.