I have to admit that one of my preferred cameras is a Sankyo, but...
for best focus indication in the viewfinder, you can't beat a groundglass. I've converted several S8 cameras to groundglass focussing because these Aerial viewfinder systems are one of the major weaknesses of S8.
The blue/yellow dichroic focus system is like the Zeiss rangefinder viewfinder on the better Polaroid Packfilm cameras. They're decent, but they demonstrate focus only at the center, and the accuracy of the system depends on the proper alignment of separate dichroic filters.
However, the sharpness a camera is not determined solely by focus or by it's focus indication system.
For instance, I found my Canon 1014xl-s sharper than my Beaulieu 4008zmII with 6-66 in normal shooting circumstances. I think this was because of the smoothness of the film transport and multi-coating on the lens. I don't have the zmII anymore, but the footage I shot with it at 75fps (which the Canon cannot do), it is significantly sharper than anything I have shot since with the 1014xl-s. That's because of the shutter speed at 75fps.
I have to agree with the previous statement that there are numerous contributing factors to the sharpness of a camera, including shooting conditions in addition to mechanical/optical considerations.
Hey, wasn't there some sort of advanced transport design in the Leicina Special?