Hi Gary,
Funny that you found that comparison! I made it years ago now...it hasn't been listed on my website for ages. In any case, I hope you love the Mamiya 7II...I think it is really one of the best of the best...to expand on the article, while the lenses are truly excellent, I now think the design of the body really has a huge impact as well. Compared to other medium format cameras (particularly 6x7), or even cameras in general, the M7II has exceedingly low mechanical vibration. The only moving part during exposure is a very small electronically controlled leaf shutter in the midpart of the lens. The shutter release is electronic, and the advance is manual, so the only moving mass during the exposure is the featherweight leaf shutter. If you use a tripod and the self-timer, this means there is hardly any vibration at all. I think we underestimate how much of an impact vibration has on image quality. Since getting the S2, this has been obvious to me -- the mirror pre-release makes a huge difference on that camera, and anyone who has used the S2 knows how well-damped it feels already!
The second thing that I think is critical is the superior film path in the M7II. In a camera like a hasselblad, the film has a convoluted path through the magazine -- the film is curled in two directions, and if it spends too long in the magazine between shots, it will develop a kink which inhibits maximum sharpness. You also have a situation where the film plane is in the magazine, rather than the camera, so the coupling needs to be perfect to have the right film plane. In the M7II, the film has a straight path from one side to the other and has a big pressure plate keeping it flat against the film plane, which is built into the magnesium chassis of the camera at the factory -- it is immoveable and consistent.
When you combine these two things with the superb lenses, the results seem to be a lot more consistently great than with a lot of other cameras.